- Aventurine
Aventurine is a form of
quartz , characterised by its translucency and the presence of platymineral inclusions that give a shimmering or glistening effect termed "aventurescence ".The most common colour of aventurine is green, but it may also be orange, brown, yellow, blue, or gray. Chrome-bearing
fuchsite (a variety ofmuscovite mica ) is the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed tohematite orgoethite . Because aventurine is a rock, its physical properties vary: itsspecific gravity may lie between 2.64-2.69 and its hardness is somewhat lower than single-crystalquartz at around 6.5.Aventurine feldspar or
sunstone can be confused with orange and red aventurine quartzite, although the former is generally of a higher transparency. Aventurine is often banded and an overabundance of fuchsite may render it opaque, in which case it may be mistaken formalachite at first glance.The name "aventurine" derives from the Italian "a ventura" meaning "to cometh". This is an allusion to the lucky discovery of aventurine glass or goldstone at some point in the 18th century. Although it was known first, goldstone is now a common imitation of aventurine and sunstone. Goldstone is distinguished visually from the latter two minerals by its coarse flecks of
copper , dispersed within the glass in an unnaturally uniform manner. It is usually a golden brown, but may also be found in blue or green.The majority of green and blue-green aventurine originates in
India (particularly in the vicinity ofMysore and Madras) where it is employed by prolific artisans. Creamy white, gray and orange material is found inChile ,Spain andRussia . Most material is carved into beads and figurines with only the finer examples fashioned intocabochon s, later being set intojewellery .Main markets for aventurine are landscape stone, building stone, aquaria, monuments, and jewellery.
See also
*
Optical phenomena
*List of minerals
*dioptase
*malachite External links
*http://mindat.org/min-436.html
http://www.wicca.com/celtic/stones/stonea-e.htm
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