Listing description
Topaz is a silicate
mineral of aluminium and fluorine
with the chemical formula Al2SiO4(F,OH)2.
Topaz crystallizes in the orthorhombic
system and its crystals are mostly prismatic terminated by pyramidal and other faces.
Detailed description
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. Topaz crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by
pyramidal and other faces.
|
|
Color and varieties
Pure topaz is
colorless and transparent but is usually tinted by impurities; typical topaz is
wine, yellow, pale gray or reddish-orange, blue brown. It can also be made
white, pale green, blue, gold, pink (rare), reddish-yellow or opaque to
transparent/translucent.
Orange
topaz, also known as
precious topaz, is the traditional November birthstone, the symbol of friendship, and the state gemstone for the US state of Utah.[5]
Imperial
topaz is yellow, pink
(rare, if natural) or pink-orange. Brazilian Imperial Topaz can often have a
bright yellow to deep golden brown hue, sometimes even violet. Many brown or
pale topazes are treated to make them bright yellow, gold, pink or violet
colored. Some imperial topaz stones can fade on exposure to sunlight for an
extended period of time.[6][7] Blue topaz is the US state Texas' gemstone.[8] Naturally occurring blue topaz is
quite rare. Typically, colorless, gray or pale yellow and blue material is heat
treated and irradiated to produce a more desired darker
blue.[7]
Mystic
topaz is colorless
topaz which has been artificially coated giving it the desired rainbow effect.[9]
Localities and occurrence
Topaz is commonly
associated with silicic igneous rocks of the granite and rhyolite type. It typically crystallizes in
granitic pegmatites or in vapor cavities in rhyolite lava
flows like those at Topaz Mountain in western Utah. It can be found with fluorite and cassiterite in various areas including Ural and Ilmen mountains of Russia, in Afghanistan, Sri Lanka, Czech Republic, Germany, Norway, Pakistan, Italy, Sweden, Japan, Brazil, Mexico, Flinders Island, Australia, Nigeria and the United States.
Some clear topaz
crystals from Brazilian pegmatites can reach boulder size and weigh hundreds of
pounds. Crystals of this size may be seen in museum collections. The Topaz of
Aurungzebe, observed by Jean
Baptiste Tavernier
measured 157.75 carats.[10]
Colorless and
light-blue varieties of topaz are found in Precambrian granite in Mason
County, Texas[11] within the Llano Uplift. There is no commercial mining of
topaz in that area.[12]
Etymology and historical and mythical usage
Etymology
The name
"topaz" is derived (via Old French: Topace and Latin: Topazus) from the Greek Τοπάζιος (Τοpáziοs) or Τοπάζιον
(Τοpáziοn),[13] the ancient name of St.
John's Island
in the Red Sea which was difficult to find and from
which a yellow stone (now believed to be chrysolite: yellowish olivine) was mined in ancient times; topaz
itself (rather than topazios) wasn't really known about before the
classical era.
Pliny says that Topazos is a legendary island in the Red Sea and the mineral "topaz" was
first mined there. The word topaz might be related to the Arabic word توباز which meant "the subject of the
search" or Sanskrit word तपस् "tapas" meaning "heat" or
"fire."[13]
History
Nicols, the
author of one of the first systematic treatises on minerals and gemstones,
dedicated two chapters to the topic in 1652.[14] In the Middle Ages, the name topaz was used to refer to
any yellow gemstone, but in modern times it denotes only the silicate described
above.
Biblical backgroud, etymology, and analysis
Many modern
English translations of the Bible, including the King
James Version
mention Topaz in Exodus 28:17 in reference to a stone in the Hoshen: "And thou shalt set in it settings of stones, even four rows of stones: the first
row shall be a sardius, a topaz, and a carbuncle (Garnet): this shall be the first row."
However, because
these translations as topaz all derive from the Septuagint translation topazi[os], which
as mentioned above referred to a yellow stone that was not topaz, but probably chrysolite, it should be borne in mind that
topaz is likely not meant here.[15] The masoretic text (the Hebrew on which most modern Protestant Bible translations of the Old Testament are based) has pitdah as the
gem the stone is made from; some scholars think it is related to an Assyrian word meaning 'flashed'.[citation needed] More likely, pitdah is derived from Sanskrit words (पीत pit = yellow, दह् dah = burn), meaning "yellow
burn" or, metaphorically, "fiery".
PRICE
$36138.29/KG OR
$16426.49/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
website: www.franchiseminerals.com
No comments:
Post a Comment