general information - styleandstones.at

frequently occurring chain silicate from the group of calcium-ambhibole.It develops mostly transparent to translucent crystals, but also occurs in the form of radial-rayed, fibrous, granular and massive mineral aggregates. Actinolite is from light green to almost black, rarely white, gray or pink.

common mineral from the mineral class of sulfates and relatives. In its pure form, its colorless or white. By foreign admixtures it can take many other colors.

rarely occurring mineral from the mineral class of phosphates, arsenates und vanadates. It is colorless, white, yellowish to greenish yellowish and develops transparent to translucent crystals.

a variety of the mineral enstatite, a frequently occurring chain silicate from the group of pyroxenes. Through its iron admixtures it gets the typical bronze color.

also "goethite" or "goethite quartz", an amethyst with inclusions of goethite tufts.

quartziferous sandstone. The different colors and harnesses caused by iron and iron-containing solutions, which have penetrated into grooves and turmoil around the quartz grains.

rarely occurring mineral from the mineral class of silicates and germanates. It is translucent and develops long, prismatic to needle-like cristals of blue to greenish-blue color with glass gloss on the surfaces.

fibrous, microcrystalline structural variety of the mineral quartz. It is colorless to bluish gray.

a very common mineral from the mineral class of sulfides and sulfosalts. Chemically, chalcopyrite is a copper-iron-sulfide. It has a gold to brass-like color with a metallic shine on the surface. After some time, the crystals may have iridescent purplish tarnish.

rarely occurring chain silicate from the mineral class of silicates. He developes translucent to opaque, massive or fibrous aggregates in violet and white stripes, where the stripes are swirled into each other and sometimes may contain dark inclusions. Charoite is highly sought as a gemstone.

silicate-rich chemical sediment from the group of pebbles. Its structure is very fine-grained and it often contains fossils. Its color is different and varies from gray, brown or green to red, but mostly between gray and yellowish, wherein the color is due to traces of additional elements or minerals.

variety of andalusite, a frequent occurring island silicate from the group of aluminosilicates. He is gray-black with graphite and carbonaceous inclusions that form the typical cross of the chiastolite. Because of this characteristic it is also known as "cross stone".

radially arrenged celestite crystsals in a dark gray to black limestone.

often occurring mineral from the mineral class of silicates and germanates. It is blue and green in various compositions and colors.

variety of microcrystalline quartz variety chalcedony. Its color is apple green ("apple green chalcedony").

a common mineral from the mineral class of sulfides and sulfosalts. Its color is a predominantly luminous, slightly tending to yellow, also known as color vermilion.

yellow-colored variety of the mineral quartz. His color varies depending on the origin of pale-green-yellow to orange to brown-orange. Its name derives from the Latin "citrus" for lemon.

coarse-grained, clastic sedimentary rock consisting at least half of rounded components (gravel or scree) cemented by a fine-grained matrix.

rarely occurring mineral from the mineral class of sulphides and thio. It is from indigo blue to blue-black color and has a grasy to semi-metallic luster.

rather rarely occurring mineral from the mineral class of halides. It has a white, brown, gray, brown-black or reddish color.

rarely occurring silicate chain from the group of amphiole. It developes transparent to translucent, columnar, bladed or fibrous crystals or fibrous mineral aggregates of grayish white, dark green or brown in color.

rather rarely occurring mineral from the mineral class of oxides and hydroxides. It has an orange, orange-red to brownis-red, but also gray to black color.

aplite, light mineral-rich, fine-grained and dense dike rocks (granite rocks). It is beige with black, irregular spots.

mineral from the mineral class of silicates and germanates, which may be abundant in various places, but overall is not very common. In its pure form, it is transparent and colorless. Through various foreign admixtures danburite can show a gray, greenish, reddish, yellowish or brownish color.

tree and shrubby crystal structures. In geology they exist for examble as crystallizations of iron and manganese oxides on rock surfaces. These are often confused with fossils and plent remains.

very common mineral from the mineral class of silicates and germanates. In pure form it is colorless and transparent. However, due to multiple refraction or other causes, it may also appear white and may assume a yellow, light to dark green or black color due to foreign admixtures. A variety is the chrome diopside, which is chromium-containing and has an emerald green color.

rather rarely occurring ring silicate from the mineral class of silicates and germanates. Its crystals have a blue-green, emerald-green to turquoise color.

also "kyanite", frequently occurring mineral from the mineral class of silicates and germanates. It has a glass-like sheen. In pure form it is colorless and transparent. It may appear white by multiple light refraction, as well as light to dark blue, blue violet, greenish to brownish and rarely red by foreign admixtures.

often occurring mineral from the mineral class of anhydrous carbonates without foreign anions. Its color palette ranges from colorless, white, yellow to brown.

rarely occurring mineral from the class of silicates and germanates. It is similar to sodalite and lapis lazuli.

orpiment with limestone. Orpiment belongs to the arsenic sulfides and is poisonous. In order to be used as a gemstone, it is stabilized. That means it is embedded in synthetic resin. Orpiment has a lemon to bronze yellow color. Eclipse is also referred to as "bumble bee jasper" and "mustard jasper".

mixture of different composition of different copper minerals. Main constituents are chrysocolla, turquoise and malachite, but also azurite. The stone is named after Eilat, a city in Israel.

variety of the silicate mineral beryl. His color is green by the addition of chromium and vanadium ions. Emerald is valued as a gemstone since time immemorial.

frequently occurring mineral from the mineral class of silicates and germanates. Its color is variable, but often dark green, sometimes yellow-brown.

growth form of quartz, the second most common mineral of the earth's crust. It arises when during the crystal growth a gap crack occurs and tears the crystal apart. During the opening of the gap, the crystal grows together again from both sides of the crack. The crack itself remains visible as a thin thread in the crystal.

large group of very frequently occurring silicate minerals with variable color ranging from colorless to white, pink, green and blue to brown.

pebble rock, which consists almost exclusively of silica which in this connection occurs in the form of i.a. very fine-grained quartz. Other minerals, such as e.g. hematite, may occur and impart color. Flint is also called "fire stone".

very often occurring mineral from the mineral class of simple halides. Pure fluorite is colorless and transparent. It can take almost all colors by foreign admixtures. Frequently common are e.g. green, violet and yellow crystals.

also "Petoskey stone", rock composed of fossilized coral skeletons.

variety of the mineral muscovite from the mica group within the mineral class of silicates and germanates. The fuchsite shimmers green because of a small proportion of chromium.

compact, coarse-grained magmatic rock of plutonic origin. It has a gray-black, occasionally a blue-green color. The light portion consists mainly of plagioclase feldspar.

by humus gel or bitumen impregnated fossilized wood in transition from lignite to hard coal. It is also called "jet", "pitch coal" or "black amber".

group of rock-forming minerals from the mineral class of silicates and germanates. Reddish color varieties predominate, even if the color palette is very variable.

a mineral belonging to the amphibole group, which is a close relative of anthophyllite.

hyalite, which is also called "crystal opal". It differs from the other opals in that typical for opals opalescences lacks in all colors. Girasol is transparent or yellow orange.

common mineral from the mineral class of oxides and hydroxides. It usually forms needle- to radial or prismatic crystals of black-brown to by weathering light yellow color.

synthetic glass, which is made of copper or copper oxide. It is often used as imitation of natural aventurine ("aventurine glass"). Color variations are reddish-brown ("gold sandstone"), blue-violet ("blue sandstone" / "blue goldstone") or more rarely green ("green goldstone").

colorless and transparent form of beryl, a commonly occurring mineral from the mineral class of silicates and germanates.

massive and relatively coarse-crystalline magmatic rocks (plutonites), which are rich in quartz and feldspar, but also contain dark minerals, especially mica.

also "witch stone", a flint with a naturally formed hole. Popular localities in Germany are the Baltic and North Sea coast.

frequently occurring mineral of the mineral class of silicates and germanates. In its pure form it is colorless and transparent. By foreign admixtures hemimorphite can take light blue, light green, gray and brown color.

a special crystal form of crystal rock (double-terminated, short-prismatic) found only in Herkimer City (New York, USA).

a collective term for an unspecified mineral from the mineral class of silicates and germanates. It usually develops leafy to tabular crystals. In its pure form it is colorless and transparent. By foreign admixtures heulandite can have a gray, yellow, pink to red, orange or brown to black color. Due to the inclusion of celadonite, a green color is evident.

green to yellowish-green variety of the mineral spodumene. The coloring is caused by admixtures of chromium. It is used exclusively for jewelry making.

quartz-rich rocks (quartzite) with inclusions of garnet and zircon. It is reddish and comes from Sri Lanka.

rarely occurring mineral from the mineral class of borates. He is frequently crossed by black-brown veins. They are similar in marbling of the popular turquoise matrix. The frequently occurring magnesite is very often mistakenly sold as howlite, even if the crystal structure is different.

general term for mixed crystals, which belong in the broadest sense of the pyroxene group. Its color varies from greenish gray and greenish black to black.

actually "cordierite", a frequently occurring mineral from the mineral class of silicates and germanates. The predominant color is deep blue to blue-violet, rarely it occurs in a greenish, yellowish brown, gray and light blue color. Colorless iolites are also known. It is also traded under the term "water sapphire".

mineral mixtures, formed mainly of jadeite or the softer nephrite. In China jade is used as a gemstone for over 8000 years.

fine-grained variety of the mineral quartz. Its range of colors and patterns is large.

also known under the term "kambaba jasper", a variety of rhyolite, a felsic, granite-like volcanic rock. For the most part it consists of quartz and feldspar. An obsolete term for rhyolite is "lipardit". The kambaba rhyolite specifically is called "eldarit".

granite with blue albite and hornblende. It is also called "kiwi agate" resp. "kiwi jasper". If the proportion of albite is low or absent, it is also called "sesame stone" resp. "sesame agate" or "sesame jasper".

a variety of the mineral spodumene. It is transparently clear, with almost complete lack of color to a dark purple. A pink color is produced by manganese additions. Kunzite is processed exclusively as a gemstone.

also disthene, frequently occurring mineral from the mineral class of silicates and germanates. It has a glass-like sheen. In pure form it is colorless and transparent. It may appear white by multiple light refraction, as well as light to dark blue, blue violet, greenish to brownish and rarely red by foreign admixtures.

relatively frequently occurring mineral mixture of albite and anorthite from the group of the feldspars and the mineral class of silicates. Striking is the iridescent play of colors in metallic gloss.

variant of crazy lace agate. Its pattern that is reminiscent of (textile) peaks, caused by the fact that the old crystal structure of calcite and zeolites, which was present in the caves before the start of agate formation, was "frozen" in this patterning.

blue shiny mineral mixture, depending on the locality of different proportion of the minerals e.g. lazurite, pyrite and calcite. He was much used by the ancient Egyptians as a gemstone.

blue-white clouded variety of pectolite, a chain silicate from the wollastonite group. It can be found in only two places - in the Dominican Republic and in Soave in Italy. Larimar is also called "Atlantis stone".

coarse-grained plutonic rocks. The bluish larvikite are anorthoclase syenite with about ten percent mica, augite and hornblende. Furthermore, there are brownish, dark green and shimmering silver variants.

rarely occurring mineral from the mineral class of silicates and germanates. It has a blue, azure, violet-blue to green-blue color and is found in particular as part of the lapis lazuli.

rock mixture of magnesite and chrysoprase, in which the proportions of chrysoprase range from little to not included.

treated rock crystal. It is irradiated and so gets its greenish-yellow color.

variety of rhyolite, a siliceous volcanic rock. His name is based on its individual pattern that is reminiscent of a leopard skin. The leopard stone is also known as leopard jasper or leopard skin jasper, although it is not a jasper.

rarely occurring mixed crystal within the group of mica. It has a predominantly white, blue-violet to pink color.

amorphous quartz glass, which most probably has arisen by a meteorite impact in North Africa 28 to 30 million years ago. It is found in the southwest of the Great Sand Sea, extending from Libya to Egypt. The sandstone has melted at high pressure and temperatures and the liquid melt thrown out. With rapid cooling in the flight phase is formed glass.

sedimentary rocks consisting predominantly of the minerals aragonite and calcite.

rarely occurring mineral from the mineral class of silicates and germanates. As a member of the serpentine group, it is one of the phyllosilicates. Its color varies from translucent green and pale yellow to white.

trade name for quartz with mineral inclusions of the chlorite group.

often occurring mineral from the mineral class of carbonates and nitrates. Its color ranges from colorless to white, yellowish to brownish and black. Magnesite is often confused with the rare howlite.

a mineral from the mineral class of oxides and hydroxides. It is the most stable connection between iron and oxygen. Magnetite has a grayish brown to black, metallic shiny color.

mineral from the mineral class of carbonates. He is a very desirable, but also a very soft stone. Therefore, it is stabilized with a mixture of synthetic resin and malachite dust. Malachite has only a green color.

chromium-rich variety of mica, a group of minerals of phyllosilicates. Mariposite imparts an attractive green color to the generally white dolomitic marble in which it is commonly found.

rock crystal steamed with titanium and iron. This treatment gives the stone a yellow to orange tint.

dendrite chalcedony resp. dendrite opal. It contains different proportions of chalcedony and opal and is characterized by its dark inclusions of iron oxides or manganese oxides. Depending on whether the proportion of chalcedony or opal predominates, it's called dendrite chalcedony or dendrite opal. The name "merlinite" is a trade name.

rock group, which consists of the minerals calcite or aragonite.

solid of cosmic origin that has crossed the earth's atmosphere and reached the ground. Meteorites are grouped into: stone meteorites, iron meteorites and stone-iron meteorites. About 5 % of all meteorites are iron meteorites made of an alloy of iron and nickel.

by far the most common coloration of quartz, the second most common mineral of the earth's crust. Due to smallest liquid inclusions or finely distributed foreign minerals, it is milky white and opaque. Practically every white quartz is a milky quartz. Another name is "snow quartz".

green, natural glasses, which emerged about 15 million years ago when a large meteorite impacts in today's Bavaria and has largely disappeared in the territory of the Czech Republic. In the impact of the meteorite on the earth's surface, this and the underlying soil were compacted, melted and thrown out at high speed. During the flight, the material cooled and froze to glass.

variety of orthoclase, which belong to the group of feldspars. It received its name due to its shimmer, reminiscent of moonlight. Moonstone is exclusively used as a gemstone.

consisting of silica. It is a type of chalcedony, that minerals of a green color in the stone contains. Despite its name and appearance the moss agate does not contain any organic material.

very common mineral of the mica group within the mineral class of silicates and germanates. It has a colorless, yellowish, brownish and rarely reddish and greenish color.

natural composite material of calcium carbonate and organic substances, which forms the innermost layer of the whole predominantly mineral part of the shell of certain mollusks. Nacre has a special surface structure and has a matt, iridescent sheen when light falls.

mixed crystal from the mixed series of the minerals tremolite and actinolite. Its colors are caused by chromium and iron and range from gray-green to dark green to almost black. Its color can also go into red brown.

a brown andalusite quartz with green patches of epidote. It is found in Australia.

rare metamorphic rock, which consists mainly of the minerals gedrite and anthophyllite. It is black and shimmers in color by inclusions. The name derives from the origin Nuuk in Greenland.

a naturally occurring volcanic rock. It is formed by the rapid cooling of lava. Its color varies greatly depending on the presence of various contaminants and their oxidation states.

a group of minerals of similar composition from the mineral class of silicates and germanates. The colors usually vary between light and dark green, but can also be yellow-brown to black.

sedimentary rock, which mainly consists of oncoids. It can consist almost entirely of round, spherical to irregularly shaped structures with a concentric lamellar structure. These nodules always have a core, e.g. a small shell piece.

opaque to slightly translucent, two-tone black and white layered, fibrous variety of chalcedony. Due to the high demand, which can not be covered by the natural resources, a large part of the commercially available onyx is imitiated. Mostly agate and chalcedony are manipulated or black obsidian is sold as onyx. If the stone is crisscrossed by white color, you can be assumed from a real specimen. For an accurate determination, however, a mineralogical investigation is necessary.

sedimentary rock consisting of small mineral spheres (ooides), which are cemented with a calcareous or clayey binder. The ooides consists predominantly of lime, iron hydroxide or silica ("lime oolite").

often occurring mineral from the mineral class of oxides and hydroxides. As an amorphous solid opal has no crystalline structure and usually occurs as massive vein filling or bulbous formed.

actually cryolite glass blurred with the opacifier cryolite. It is milky-white, translucent but not transparent. Opal glass is used as moonstone imitation.

common opal without the typical opal opalescent colors. Mineralogical it is a hydrous silica.

corneous and calcareous anatomical structure like a trapdoor which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of trapdoor to close the aperture of the shell when the soft parts of the animals are retracted.

living in the sea first representative of the nautiloids with a cylindrical shell, which were divided into segments. Their age is about 280 to 380 million years.

round grinded loose sediment. Gravel is a typical sediment of flowing waters with a steep gradient.

a variety of olivine, a group of minerals of similar composition from the mineral class of silicates and germanates. Its color usually varies between light and dark green, but can also be yellow-brown to black.

rarely occurring phyllosilicate, which is colorless and transparent in pure form. By foreign admixtures it can assume a yellowish-gray and rarely reddish and greenish color.

fossils that arise through the process of silicification. In their structure, the plant can often be detected.

rock crystal with visible growth layers. Among collectors, he is highly sought.

rather rarely occurring mineral from the mineral class of phosphates, arsenates and vanadates. It can be colored colorless, pink, red, purple or brown.

variety of marble that has emerged from the metamorphism of limestone and occurs as coarse to medium-grained stone of recrystallized dolomite or calcite. Its color range includes a combination of black, rust red, light brown, yellow and white.

rare mineral from the mineral class of silicates and germanates. It has translucent to opaque crystals of reddish brown to deep red or reddish purple to almost black color.

variety of the mineral chalcedony with inclusions of amphibole minerals. Its fibers create a shimmer, similar to that of tigers eye.

also pinolite-magnesite, a rarely occurring rock that consists of magnesite-dolomite and graphite, and is formed only under special conditions inside the Earth's crust. Pinolite is found in high quality in the Hohentauern in Austria. It is reminiscent of edelweiss due to its flower-like grain, which is why it is also known under the trade name "edelweiss magnesite", but also under "ice flower magnesite".

rock that emerges through silicification of the original rock. It is white and can accept by impurities also a dark blue or gray color.

a variety of the mineral quartz. It is a leek green, opaque aggregate that gets its color from actinolite inclusions.

massive quartz with silicate inclusions. It is also referred to as "green quartz" or "budstone".

also green quartz, green amethyst or "vermarin", a leek green, transparent variety of quartz.

often occurring mineral from the mineral class of silicates and germanates. It has a white, gray or yellowish to greenish color. Also colorless prehnites and cat's eyes prehnites are known.

sandstone, which is colored by iron oxides. Its different colored layers are characteristic, ranging from beige to pink and red. It is also known as "zebra iron jasper" or "print stone jasper", even if it is not a jasper.

rarely occurring mineral from the mineral class of phosphates, arsenates and vanadates. It is translucent to opaque and does not form any visible crystals. Purpurite has a reddish violet to deep dark pink color.

very often occurring mineral from the mineral class of sulfides and sulfosalts. It consists of iron and sulfur and is also known by the term "fool's gold".

second most common mineral of the earth's crust. Pure it is completely transparent and colorless and is called "rock crystal". Due to the inclusion of colored minerals or other causes, quartz can be colored differently. Yellow to orange brown quartz is called "citrine", violet as "amethyst", pink as "rose quartz", etc.

a variety of rhyolite, a felsic, granite-like volcanic rock. For the most part it consists of quartz and feldspar. The typical bright areas of the rainforest rhyolite consist of stocks of chalcedony. An obsolete term for rhyolite is "lipardit".

often occurring mineral from the mineral class of carbonates and nitrates. Its color ranges from pink to gray-brown, white and yellow and a black outer crust.

rarely occurring silicate mineral from the class of silicates and germanates. Its colors are pink to red, brownish-red or gray-yellow, often crossed by black manganese oxide veins.

felsic volcanic rock and therefore in its chemical and mineralogical composition similar to granite. It usually has a relatively bright color. Gray, light green or light red colors dominate. The rhyolites include i.a. the leopard-rhyolite and the Dr.-Liesegang-Stone (wonderstone).

relatively rare occurring chain silicate from the group of amphiboles. It develops crystals of yellow, brown, gray-violet, dark red to dark green or blue color.

transparent and colorless variety of the mineral quartz. It's valued as a gemstone since ancient times.

variety of the mineral quartz. It has a pink coloration.

red variety of the mineral corundum. The characteristic color is due to small admixtures of chromium. Rubies are mainly used as jewelry stones.

mineralogical corundum in silicate-rich rock. This combination arises from the fact that kyanite forms around the ruby. Then fuchsite formes around these crystals.

actually anyolite, metamorphic rock composed of the green mineral zoisite, the red, opaque ruby, a variety of corundum and often black inclusions of amphibole minerals.

frequently occuring mineral from the mineral class of oxides and hydroxides. Its color varies between reddish brown and strong red, but also golden yellow, bluish and purple.

quartz with rutile needles. Rutile is a frequently occurring mineral from the mineral class of oxides and hydroxides. Rutilated quartz is also known as angels hair and venus' hair.

bizarre crystal structure which usually consists of sand grains. These are embedded in a crystal of gypsum or barite. They are water soluble and occur during hot, dry desert areas.

clastic sedimentary rock containing at least 50 % sand grains, which mostly consists of quartz.

variety of the mineral corundum. It will be assigned to all colorless and colorful colored varieties with the exception of the red ruby. In a narrower sense, the term refers today to the blue color variants.

variety of carnelian, the red- to orange-white form of banded chalcedony. Sarder has a reddish to flesh color and is also called "sardis".

variety of onyx, a black and white layered, fibrous variety of chalcedony. Sardonyx is banded brown and white, with the brown color being from the sarder, a reddish to flesh-colored variety of carnelian, which in turn is a variety of chalcedony.

band-like alternation of brown sphalerite and mostly yellow wurtzite, as well as other admixtures, e.g. Galena.

frequently occuring mineral from the mineral class of sulfates. In its pure form it is colorless and transparent. By foreign admixtures scheelite can take on a gray, brown, light yellow, yellow-orange, red and green color.

manmade pearls, whose core was achieved with nacre dust.

a collective term for different tectonically deformed and partly metamorphic sedimentary rocks.

gray-brown to black variety of the mineral quartz. He is also known under the name "Morion".

mineral from the class of silicates and germanates. It is using for making jewelery, as well as a decoration in the aquarium hobby.

natural agatized quartz that is sliced from stalactites in clear, white or gray, with mossy inclusions.

frequently occurring mineral from the mineral class of oxides and hydroxides. Its color ranges from colorless, red, orange, yellow, green, blue, violet, brown to black.

frequently occurring neosilicate. It has a reddish-brown to brown-black color.

basic, magnesium-containing mineral, which is formed during the conversion of chromite-containing serpentine. It has a pink to violet color and is rarely offered completely pure. Inclusions of stichtite in serpentine is called "atlantisite".

mineral from the mineral class of silicates and germanates. It is either colorless or white, yellowish, pink to reddish and brown color.

biogenic sedimentary rock that is created by certain circumstances in a body of water.

rarely occurring mineral from the mineral class of carbonates and nitrates. In pure form is is colorless and transparent. It can also appear white by multiple light refraction.

rarely occurring mineral from the mineral class of silicates and germanates. He has a purple to brownish purple color. Sugilite is also sold under the name "new age stone".

medium to coarse-grained magmatic plutonic rock rich in feldspar and poor in quartz. Due to its mineral content it usually has a light gray or reddish color, but occasionally it can be very dark.

schisty metamorphic rock consisting mainly of talc, a very common layered silicate.

blue variety of the gray to brownish mineral zoisite. It's only used as a gemstone.

glass object, which is of terrestrial origin but whose formation is caused by the impact of large meteorites on earth's surface. Earthly material is melted during the felling and is thrown away up to several hundred kilometers, where it solidifies to glass.

rather rare occurring mineral from the mineral group of oxides and hydroxides. It is grayish-black in color and appears brown in translucent light and gray with a golden tint in reflective light.

pink variety of zoisite, a rather rarely occurring mineral from the mineral class of silicates and germanates.

golden brown to golden yellow variety of the mineral quartz. The shimmering surface reminds of the cat's eye effect.

lay-shaped structured sedimentary rock, which consists e.g. of the minerals hematite and jasper. t is used for gemstones only.

also called "sphene", a frequently occurring mineral from the mineral class of silicates and germanates. In its pure form it is colorless and  transparent. By foreign admixtures it can take a green, yellow, red, gray or brown to black color.

often occurring island-silicate. Only the blue topaz occurs naturally very rare. Topazes are processed into gemstones.

extinct class of sea-dwelling arthropods, which are among the key fossils of the earth's history.

rarely occurring, hydrous copper-aluminum-phosphate from the mineral class of phosphates, arsenates and vanadates. Its characteristic blue-green color owes its name to the color turquoise. Turquoise is used exclusively for gemstones and is often imitated, e.g. dyed magnesite, howlite and jasper.

also known as turitella jasper, fossil freshwater snails of the extinct species "elimia tenera" in agate. It is also referred to as snail agate.

ring silicate whose color palette is extremely variable and can even vary along the longitudinal axis of a single crystal (e.g. "watermelon tourmaline"). Known color variants are red and pink ("Rubellite"), blue ("Indigolite"), green ("Verdelite"), brown ("Dravite") and black ("Schorl"). Tourmaline is used as a gemstone.

quartz with black tourmaline inclusions. Tourmaline is a ring silicate, which is named "Schorl" in its black variety.

rock, which is composed of the minerals epidote, feldspar and quartz. Its colors are green and pink.

rarely occurring island silicate from the garnet group. It usuallly develops small, well-formed to perfect crystals, but also granular aggregates. The color of uvarovite fluctuates from dark to emerald to brown-green due to the formation of mixed crystals and foreign admixtures.

mineral from the mineral class of phosphates, arsenates and vanadates. In its pure form it is transparent and colorless. It can be interspersed by greenish, bluish-green and - rarely - red and brown matrix by foreign admixtures.

rarely occurring mineral from the mineral class of silicates and germanates. It has a green, yellow, light blue, violet or brown color. Colorless crystals are also known.

rock, that arises as a result of volcanic activity by rapid cooling of molten rock at the surface and thus a rhyolite. Mostly it is to be feldspar, blue chalcedony and basalt. It is also called "que sera stone".

a variety of marble, a carbonate rock, which consists of the minerals calcite, dolomite, and aragonite. Zebra marble is black/white and is commercially often sold under the name "zebra jasper".

rarely occuring mineral from the mineral class of silicates and germanates. In its pure form it is colorless, but can be gray to yellow, green, pink to red or blue to purple in color due to various admixtures.