Beauty hardness and rarity, these are three characteristics which determine precious gems. Gem which has at least one characteristics from above can be considered as precious. Its rarity, need of hard work and individual characteristics determine its cost. Precious gems are at the same time good investments, its rarity and durability. Ind whole world such stones are becoming points of interest for many. Many fabricated stones are used in industry but only natural ones maintain their value and full beauty. These stones are: Ruby, Sapphire, Emerald, Pearl and Tanzanite.
Tanzanite is the blue/purple variety of the mineral zoisite (a calcium aluminium hydroxy silicate) which was discovered in the Mererani Hills of Northern Tanzania in 1967. It is used as a gemstone. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet and burgundy depending on crystal orientation. In nature it is found as big crystals which can be about 10-50 karats.
A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). The red color is caused mainly by the presence of the element chromium. In old east ruby was considered as most valuable stone. On sannskrit language it was called "manakia" meaning king of stones.
Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide.Trace amounts of other elements such as iron, titanium, chromium, copper or magnesium can give corundum blue, yellow, pink, purple, orange or green color. Name of stone comes from old Greek word, which on the other hand was connected to Jewish word "sappir". Another version suggests that it comes form Babylonian word "sipiru" which meant "scratching". The latter version is more believable considering durability of stone.
Emerald is a variety of the mineral beryl colored green by trace amounts of chromium. Beryl has a hardness of 7.5–8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. Name of stone is coming from Persian word "zumurund", which means green color.
A pearl is a hard object produced within the soft tissue of a living shelled mollusk. Just like the shell of a clam, a pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. Pearl as word comes from old Greek language.