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10.7" White Aragonite and Calcite Formation - Fluorescent
This is a beautiful formation of fluorescent calcite with aragonite, from Morocco. When viewing the mineral under natural and artificial light, aside from the interesting white botryoidal formations, the mineral may seem slightly uninspiring. But when placed under shortwave UV light, this mineral fluoresces a white-green color and displays a phosphorescence that lingers for a short period of time following removal of the UV light.
Stalactites form when water that seeps through rock, reaches an opening such as a cave or tunnel. Once this mineral rich water (calcite in this case) precipitates out of the rock wall/ceiling, it leaves behind a crystal as the precipitate builds with each drop of water. Stalagmites are likely to form from this process, for the drops from the ceiling will still contain high mineral content, typically depositing a precipitate that will continue to build as long as water continues to flow in this location.
Aragonite is a carbonate mineral, one of the two commonly occurring crystal forms of calcium carbonate, the other form being calcite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. It's crystal lattice differs from calcite, resulting in a different crystal shape. Aragonite forms naturally in most mollusk shells, and as the calcareous endoskeleton most corals.