Crocoite is one of the loveliest of all collector stones. It's too soft and brittle for wear, but it is quite a rare mineral and relatively few stones have been cut. The dispersion is high but completely masked by the intense body color.
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|Crystallography||Monoclinic. Crystals prismatic, sometimes hollow.|
|Colors||Red-orange, cherry red. orange, yellowish.|
|Luster||Adamantine to vitreous.|
|Stone Sizes||Gems can be up to about 10 carats, but these are usually not transparent. Clean stones up to 1-2 carats are available in deep red-orange color from Tasmania. Devonian Group (Calgary, Alberta, Canada): 14.5 (orange, Tasmania). Smithsonian Institution (Washington, D.C): 5.7 (orange-red, Tasmania).|
|Luminescence||Weak reddish to dark brown (SW); weaker effect in LW.|
|Spectral||Distinct band at 5550 but seen only in thin fragments. Transmits mainly in the yellow-red region of the spectrum.|
|Pleochroism||Orange-red to blood red.|
Optics: a= 2.29-2.31; β = 2.36; γ = 2.66.
Biaxial (+), 2V= 57°.
Occurrence: Secondary mineral in oxidized zones of lead deposits.
Dundas, Tasmania: best crystals found in the world, some gemmy; large clusters.
Beresov District, USSR: red crystals.
Tiger, Arizona: very tiny crystals.
California; Minas Gerais, Brazil
Comments: Crocoite is one of the loveliest of all collector stones. It’s too soft and brittle for wear, but it is quite a rare mineral and relatively few stones have been cut. The dispersion is high but completely masked by the intense body color.
Name: From the Greek krokos, meaning saffron, in allusion to the color.