Opal Pseudomorphs

July 18, 2023

Mila_opal_image (003)a

Mila_opal_image (004)

Photographer: Mila Zinkova   

Summary Author: Mila Zinkova   

Opal is a silicate and silica doesn't crystallize. However, sometimes opal can replace other mineral crystals during rock formation. Such opals are called "opal pseudomorphs." Two such examples are shown above. It's not exactly clear what the original mineral was that created these crystals, but there's a remote possibility that it was of organic origin (perhaps fossilized vegetation) rather than mineral based. Click here to see the play of colors of the specimen at top. 


Related Links:

Color in Opals

Video - Part 2 (note strange reflection)