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Opal

Opale

MNHN N°200.244

visu_499 infos
FROM : Coober Pedy, Australia
SIZE : 22 x 12.5 x 5 cm

general description

It is a pseudomorphosism of two fossils (rostrum of belemnite) in opale, captured in a matrix of limestone. The fossils have a beautiful iridescence.

This sample has been acquired thanks to special subventions for the renovation of the national Museum of Natural History and comes from Coober Pedy in Australia.

It is currently exposed in the Treasure Room, within the Gallery of Mineralogy of the Muséum national d’Histoire naturelle.

Photography: A. Dahmane / Photo Saint-Hilaire, © MNHN.
The Species page
Identity card
SPECIE : Opal

HISTORY : Name derived from the Sanscrit "upala" meaning a precious stone; name giving later "opalus" in Latin

CHEMICAL FORMULA : SiO2 nH2O
CRYSTAL SYSTEM : Amorphe
COLOR : White, blue, yellow, violett, red, black, irisations
DIAPHANIETY : Transparent to opaque
LUSTER : Vitreous to pearly
STREAK : White
MORPHOLOGY : Amorphe
HARDNESS : 5,5-6,0
DENSITY : 1,99-2,25

CHEMICAL CLASS : IV - Oxides and hydroxide
GROUP : Moganite - opale series
STRUNZ CLASS BEFORE 2001 : 4/D.01-80
STRUNZ CLASS AFTER 2001 : 4.DA.10
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