The Galaxy Opal is the world's largest polished
opal
Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline form ...
, certified by the
Guinness Book of World Records in 1992.
["The Guinness book of records, 1993" October 1992, ]
p.22
/ref> It was found at the Boi Morto Mine in Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
in 1976. The finished opal weighs approximately 3,749 carats, or 0.75 kg. It was carved from a grapefruit-sized piece of rough stone weighing 5,205 carats by Scott Cooley into a shape resembling a child's head. The weight of the finished stone was beyond the capacity of any gem measuring scale at the Gemological Institute of America
The Gemological Institute of America (GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. Founded in 1931, GIA's mission is to protect buyers and se ...
and an approximation of its weight in carats had to be determined using a postal scale. The stone measures 14.0 x 10.2 x 4.1 cm (5-1/2 x 4 x 1-5/8 in). It is currently part of a private collection.
See also
* List of individual gemstones
A number of gemstones have gained fame, either because of their size and beauty or because of the people who owned or wore them.
A list of famous gemstones follows.
Alexandrites
* Smithsonian museums' Alexandrite, the largest cut alexandrit ...
Other notable individual opals:
* Andamooka Opal
* Flame Queen Opal
The Flame Queen Opal is perhaps the most famous of all opals. It is the best-known example of “eye-of-opal”, an eye-like effect created when opal in-fills a cavity.
The Flame Queen's flat central raised dome flashes red or gold depending on t ...
* Glorious Jubilee
* Halley's Comet Opal
* Olympic Australis Opal
References
{{Reflist
External links
Photograph of Galaxy Opal
Individual opals
Individual gemstones