Topaz can be found in a variety of colours: green, yellow, red, pink, gold... and also in blue, which is undoubtedly the most popular for this gemstone. This colour is difficult to find, however, and some of the most important deposits are located in England (Cornwall), Scotland and Northern Ireland. The deep tones of blue topaz add depth to any piece of jewellery; perhaps that's why it's one of the most popular gemstones.
Color: Colorless, yellow, orange, blue, pink, violet, light green
Moh's hardness: 8
Chemical composition: Al2 [(F,OH)2[SiO4] Fluor containing Aluminium silicate
The name probably derives from the Arabic word Faridat (Gem) but commonly used by the name Olivine because of its olive-green color. It has a vitreous and greasy luster. The deposits have been found in Australia, Burma, Zabargad, Arizona, Norway, Sri Lanka Mexico, Kenya and Tanzania.
Moh's hardness: 6.5-7
Chemical composition:Mg,Fe2+[SiO4] Magnesium iron silicate
The name is derived from its lemon yellow color. The coloring agentis iron. Natural citrines are rare. Most comercial citrines are heat-treated amethyst, so all Roosik & Co gemstones are NATURAL NOT TREATED, We buy the citrines from deposits of natual-colored citrines found in Spain, Brazil and the Unitated States.
Color: Light yellow to dark, gold-brown
Moh's hardness: 7
Crystal system: Hexagonal