Fig. 1: Calcium sulfate spherulite found in Winnipeg, Manitoba, Canada.
From: Controlled spherulitic crystal growth from salt mixtures
Despite its complex appearance, it is composed solely of gypsum (calcium sulfate, CaSO4 ⋅ 2H2O). Large amber-colored bladed gypsum crystals can be seen on top of the polycrystalline gypsum macro spherulite. The bladed crystals grew during a secondary stage of crystallization. Collection of the Gallery of Mineralogy and Geology in Paris, France.
