Gypsum Selenite

Water-Clear Selenite

This is a very unusual, natural form of the mineral gypsum. Across the world, gypsum is a common mineral in oceanic and saline waters. When the environments are isolated – think of the Great Salt Lake – concentrations of gypsum can become so high that the mineral precipitates out of solution. In most cases, the resulting gypsum crystals are clouded and colored by impurities. White Sands National Monument is another example of massive gypsum occurrence. All the sands there are composed 100% of gypsum which formed on the floor of an inland sea eons ago. As the water dried up, the gypsum accumulated in massive quantities.

How They Formed

These particular crystals are unique in their extreme clarity. Pure, water-clear crystals like this form only in a very quiet environment – in this case it was a segment of inland sea that covered southern Utah and northern Arizona during the Triassic 200 million years ago. In rare cases such as this, the waters are so still the gypsum grows without any disturbance, resulting in clear crystals free of inclusions or impurities. Pure gypsum is softer than your fingernail and scratches easily, so care must be taken in handling it. The crystals have perfect cleavage and can be split again and again into very fine sheets. “