Aquamarine: Aquamarine is a form Beryl that is similar in color to sea water. So it varies from green to blue just like the oceans. Most if not all Aquamarine has been heat treated to improve or lighten the color. Currently the most popular and therefore valuable colors of Aquamarine Beryl are the light "sky" blue versions. If Aquamarine receives large amounts of heat treatment it will bleach or be (read full)

Achroite Tourmaline: Colorless Tourmaline, also known as white or Achroite Tourmaline is the name given to the clear or colorless version of Tourmaline. The word achroite is Greek for colorless. If you are into birthstones then Achroite Tourmaline is one of the ones used for October. If you follow the zodiac then it's used to represent Libra. Tourmaline in general is found on every continent and is possibly the (read full)

Amethyst: Amethyst is the most coveted stone in the quartz group, and it is sometimes confused with beryl. It is usually found layered with milky quartz, and its color varies from purple to violet. It is sometimes sold as Ametrine, but this is actually a combined variation of 2 gems; Amethyst and Citrine. Amethyst like Agate Chalcedony can be found in geodes. There are many types of synthetic Amethyst aro (read full)

Sard: Sard is the uniformly colored red-brown or brownish-yellow variety of Chalcedony, which in turn is a microcrystalline variety of Quartz. There is no strict separation between sard and cornelian/carnelian (red to reddish brown), because they are both chalcedonies found in the same deposits and were employed for the same objects. The tints of a sard stone may be reddish or orange. Good-quality mat (read full)

Platinum: Platinum is a rare and precious metal that occurs as a Native Element, one of the rarest in the Earth's crust. It resembles silver, but it is less reactive and does not tarnish in air, and is thus considered a noble metal. Its greater hardness, higher density, and high melting point also distinguish it from silver. Like gold, another noble metal, the only common acid combination to dissolve it i (read full)

Carnelian: Carnelian is a variety of chalcedony, which is translucent and is red to reddish-brown. It may also occur as flesh-colored chalcedony, known as cornelian or carnelian. It is slightly similar in appearance to its relation, the dark brown chalcedony, sard. The colour of cornelian is caused by colloidally dispersed hematite. Other reddish chalcedonies may have been colored by heating since if they (read full)

Zoisite: Zoisite is a hydrous calcium aluminum silicate in the Epidote group, with an orthorhombic crystal system, three crystal axes at right angles to each other, all of varying lengths. It appears in elongated, prismatic crystals, with fine parallel lines on the prism faces and usually poorly terminated. It also appears frequently in formless grains, poorly-defined crystals, rodlike aggregates and gran (read full)

Morganite: Morganite is a pale red-purple, rose, salmon to purplish red, slightly pink, cesium-bearing variety of Beryl. The Beryl group of silicates includes the important gem varieties emerald, blue aquamarine, pink morganite, and red and yellow beryl. The color of morganite is usually a soft pink without any overtones. It has glassy luster, like other beryls, but its pleochroism is not noticeable. The p (read full)

Citrine: Citrine is an attractive type of quartz, which is the commonest mineral on the earth's surface. But citrine itself is an uncommon macrocrystalline variety. Its yellow color brought about by its iron hydrate content, its reddish yellow from a trace of ferric iron. It forms hexagonal prisms, terminated by pyramidal shapes. Its faces are often striated, and the crystals twinned and distorted, having (read full)

Silver: Silver is a Native Element with an isometric system, a soft, white, precious metallic element of group 1 of the Periodic System with the symbol Ag. It appears as cubes, octahedrons, and dodecahedrons, and rarely as crystals. Native silver cubes are always small, usually displaying stepped faces, or in compact masses of twining branches, and wirelike forms of a silvery, gray-white color. Aggregate (read full)

Rubellite Tourmaline: Rubellite is the pink to red variety of Tourmaline, which is a complex borosilicate of aluminum and alkali, with iron, magnesium, and other cations. It is found as fine acicular crystals in rocks, or as large individual crystals grown upon matrix where they may reach a weight of several kilograms. Most form elongated and striated trigonal (three-sided) prisms and these are terminated with trigona (read full)

Tektites: Tektites are glass specimens rich in silica that many believed were actually meteorites. But, the locations in which tektites have been found, and their chemistry, led scientists to suggest that they may not in fact have come from outside planet Earth. Another conjecture is that tektites are formed from rocks that melted after being hit by a meteorite. Tektites actually have a composition not unl (read full)

Moonstone: The variety name Moonstone is usually used to describe an optical effect and unlike most variety names it is not confined to a single species (The term is also applied to albite-moonstone, microcline-moonstone, labradorite-moonstone). But Moonstone most prominently refers to the orthoclase feldspar, Adularia Moonstone, a microperthitic association of orthoclase and albite) and rarely to Albite M (read full)

Emerald: Emerald is the most prized variety of the mineral Beryl. It sometimes fetches higher prices than diamond. It appears as pale green to bright green. Though it is the green variety of beryl, not all gem-quality green beryls are called emeralds; yellow-green stones are called "heliodors;"soft blue-green or even pale green specimens are called "aquamarines." The typical color of emerald is a bea (read full)

Coral: Corals are the supporting framework of small polyps. Each coral polyp, a tiny marine animal that lives in enormous colonies, extracts calcium carbonate from the sea and exudes it through their bases to build a protective home around and above itself. Each generation of polyps dies in its protective home and each succeeding generation builds on top of its predecessor. They precipitate calcareous m (read full)

Zircon: Zircon is a zirconium silicate with a tetragonal crystal system, and also contains thorium and uranium. It appears as stubby, prismatic, isolated or sometimes dipyramidal, like two pyramids connected at their bases; or in twins, colorless to yellow, red, brown, gray or green, in irregular granules. It is very hard, heavy, with indistinct cleavage, and shell-like fracture. It is sometimes perfect (read full)