Topaz is derived from the Indian Sanskrit word tapas, meaning fire. It is an aluminum, hydroxyl-flourine silicate. Strong chemical bonding makes it the hardest of the silicate minerals. It crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces, the basal pinacoid often being present. It has an easy and perfect basal cleavage, meaning that gemstones or other fine specimens have to be handled with care to avoid developing cleavage.
Topaz typically occurs in cavities in rhyolites and granite, in pegmatite dikes, and in high-temperature veins with cassiterite and tourmaline. A common misconception is that all topaz is yellow. It is most commonly colorless, but colors include blue, pale green, and the spectrum of yellow through sherry orange to pink, and most unique, red.
During the Middle Ages topaz was thought to strengthen the mind and prevent mental disorders as well as sudden death. It assists in general tissue regeneration and is valuable in the treatment of hemorrhages. It also increases poor appetite and helps fighting blood disorders. Topaz also balances emotions and calms passions and has been considered a "cooling" gem, much like ruby is considered a "hot" gem. Topaz was thought to have the ability to quickly cool boiling water and flaring tempers.
Topaz has a hardness of 8 in Mohs scale, a specific gravity of 3.4–3.6, and a vitreous luster. It is also believed that topaz along with citrine are birthstones of a person born under the zodiac sign of Scorpius (Scorpion) from Oct. 24 - Nov. 21 and the anniversary gemstone for the 4th and 19th year of marriage. Imperial topaz is the anniversary gemstone for the 23rd year of marriage.
0 comentarios:
Post a Comment