Rocks and Minerals Gallery
Orthoclase
Composition: Potassium aluminum silicate
Uses: Orthoclase is industrially important in the manufacture of glass and ceramics. Crystals and twins are studied by scientists, as they provide information on the formation of minerals and environmental factors. Well shaped crystals and twins are highly sought after by mineral collectors, and the variety Moonstone is an important gem. A transparent yellow variety from Madagascar is faceted as a gem for collectors.
Peridotite
Composition:Made up almost entirely of small grains of olivine, or pyroxene may be present in appreciable amounts.
Uses: As a source of valuable ores and minerals, including chromite, platinum, nickel and precious garnet. Diamonds are obtained form mica-rich peridotite (kinmberlite) in South Africa.
Pyrite
Composition: Iron sulfide, sometimes containing small amounts of cobalt, nickel, silver, and gold.
Uses: Pyrite was polished by the Native Americans in the early times and used as mirrors. Today, it is used as an ornamental stone, as well as a very popular stone for the amateur collector. It is sometimes used as gemstone by being faceted and polished for use as a side jewel in a ring, necklace, or bracelet. Pyrite is many times wrongly called "Marcasite" in the gem trade. Although the mineral Marcasite has the same composition as Pyrite, it is a different mineral. Marcasite is not suitable for gem use, because it powders and may disintegrate into a powder.
Sulfur
Composition: Gold, with small amounts of silver; sometimes also copper and iron
Uses: Gold has been used as a precious metal throughout the history of mankind. This is due to its resistance, beauty, rareness, and the fact that it is very easy to work with. In addition, in the olden days gold didn't have to be extracted, because a large amount was found in a pure state. Many gold ornaments from the past have been found. Most noted are from the tombs of the Pharaoh in Egypt, where gold masks, statues, coins, and much jewelry was archeologically excavated. Gold has been used for coinage throughout the centuries, and is currently accepted internationally as a standard value. Nowadays the main use of gold is for jewelry.
Due to gold's distinctive properties as a metal, it has several industrial uses. It is also used for photography, dentistry, coloring, and being studied for treatments in cancer.