Roger Weller, geology instructor
email@example.com copyright 2011-R.Weller
selenite cleavage containing inclusions
of water and gas bubbles-2
Penfield Quarry, New York
If a gypsum crystal (selenite) grows at a rapid rate, there may be incomplete crystal
growth resulting in the production of small cavities with the growing crystals.
Since the material is crystalline, the cavities may take on a shape resembling the
selenite crystal; these cavities are termed "negative crystals". Since the crystals
are being formed within a solution, small amounts of the solution along with gas
bubbles gets trapped within these cavities.
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Just credit photo to R.Weller/Cochise College.