fulgurite - set of natural glass tubes formed by lightning strikes on sand Because kaolinite does not absorb

Because kaolinite does not absorb water

it becomes a dull gray-green

it does not expand when it comes in contact with water and is the preferred type of clay for the ceramics industry

and is frequently found in schists that formed at medium to high pressures and lower temperatures in areas of regional metamorphism

the 'Gypsum' cave

fulgurite - set of natural glass tubes formed by lightning strikes on sand Because kaolinite does not absorbFulgurites form when a lightning bolt strikes the earths surface, fusing the material into a glass tube, sometimes with a hollow center. When lightning strikes sandy soil, the air and moisture in the sand are rapidly heated. Quartz sand melts at a temperature of roughly 1600C to 2000C depending on the moisture content. The name comes from the Latin fulgur, for lightning. These were collected from a Sahara dune field in Morocco. Though the seller did