Mother of Pearl:
Mother of pearl is the common name for iridescent nacre, a blend of minerals that are secreted by oysters and other mollusks and deposited inside their shells, coating and protecting their bodies from parasites and foreign objects.
Nacre is the same substance that is deposited around an object that becomes lodged in the mollusk--either naturally or inserted by humans--to become a pearl.
Although pearls are popular today, some past cultures regarded colorful pieces of mother of pearl as more desirable decoration for jewelry and other objects.
Jewelry made from mother of pearl is in the group called organic jewelry, which includes all jewelry that originates from a living creature, plant or other living organism
Quartz Crystal:
Quartz (silicon dioxide or SiO2) is the most common single mineral on Earth. It comes in many colors and shapes, but it always has a glassy luster and it always is hardness 7 on the Mohs scale.
Quartz also can be brown (morion) or black (smoky quartz) or purple (amethyst), rarely green and other colors depending on the impurities in it.
Pure, clear quartz is called rock crystal. Crystals always show a six-sided outer form, but inside, when you break them, they have almost no cleavage direction. Instead they display a conchoidal fracture, in which the broken surfaces show scooped-out, shell shaped forms. Conchoidal fracture and the glassy luster are very typical signs of quartz.
Quartz is found in most geologic settings, but it most typically forms sedimentary rocks like sandstone and is the defining mineral of igneous rocks like granite.
Quartz is an old German word that originally meant something like hard or tough.
African Jade:
aka Buddstone, Garnet Jade, Grossular Garnet, South African Jade, Transvaal Jade
This gemstone is mined in the reaches of Africa, and for this reason gets its name. It is not a real jade, but actually an opaque grossular garnet that resembles jade. Grossular garnet is a silicate of calcium and aluminum. It is used as an inexpensive substitute for jade, and is often a mix of colors including white, light green and pink. The term "grossular" comes from the Latin word for "gooseberry," as the stone's pale green color resembles that of a gooseberry.
Garnet:
The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. Garnets are most often seen in red, but are available in shades of green, yellow, orange and a wide variety of colors spanning the entire spectrum except blue.
Its green variety, called tsavorite, is a good inexpensive substitute for emeralds. Another green variety Demantoid is a lot more brilliant than tsavorite, hence it is much more expensive.
Garnet's red variety Pyrope is a good substitute for rubies and yellow variety Hessonite is taken for topazes.
The name "garnet" comes from the Latin granatus ("grain"), possibly a reference to the Punica granatum ("pomegranate"), a plant with red seeds similar in shape, size, and color to some garnet crystals.
Cinnabar:
Cinnabar, sometimes written cinnabarite, is a name applied to red mercury sulfide, or native vermilion, the common ore of mercury. The name comes from the Greek - "kinnabari"
Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color. It occasionally occurs, however, in crystals with a non-metallic adamantine luster.
The most popularly known use of cinnabar is in Chinese carved lacquerware, a technique that apparently originated in the Song Dynasty. The danger of mercury poisoning may be reduced in ancient lacquerware by entraining the powdered pigment in lacquer, but could still pose an environmental hazard if the pieces were accidentally destroyed. In the modern jewelry industry, the toxic pigment is replaced by a resin-based polymer that approximates the appearance of pigmented lacquer.
Turquoise:
Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium
It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue.
The color of turquoise ranges from blue through various shades of green to greenish and yellowish gray. A delicate sky-blue, which provides an attractive contrast with precious metals, is most valued for gem purposes. Numerous deposits of turquoise in the southwestern U.S. have been worked for centuries by American Indians. The mineral also occurs in Iran, northern Africa, Australia, and Siberia.
Malachite
Malachite, a copper carbonate is found in varying shades of green.
The coloring agent is copper, and malachite is formed from copper-containing solutions in or near copper ore deposits. This oxidation zone of copper deposits also creates azurite, limonite, and chalcopyrite, which are all found in association with malachite. The most important geographic locations are in Zaire, as well as the Ural Mountains, where massive blocks were mined and became wall paneling and table tops for Russian czars. Malachite also comes from Australia, Chilie, Namibia, Zimbabwe, and Arizona, Nevada, and California, in the US.
Peridot:
Peridot is the gem quality variety of forsteritic olivine.
The name of the gemstone is believed to come from either the Arabic word faridat meaning "gem" or the French word peritot meaning "unclear." Peridot is one of the few gemstones that comes in only one color. The depth of green depends on how much iron is contained in the crystal structure, and varies from yellow-green to olive to brownish green.
Peridot is also often referred to as "poor man's emerald". Olivine is a very abundant mineral, but gem-quality peridot is rather rare. Peridot crystals have been collected from iron-nickel meteorites.
Carnelian:
Carnelian, sometimes spelled cornelian, is a red or reddish-brown variant of chalcedony.
The word is derived from the Latin word meaning horn, in reference to the flesh color sometimes exhibited. It was used widely during Roman times 2,000 years before the present era to make signet or seal rings for imprinting a seal with wax on correspondence or other important documents. Hot wax does not stick to Carnelian.
|
