SrB₆O₉(OH)₂.3H₂O

This sample of tunellite is displayed in the Smithsonian Museum of Natural History. Tunellite is an oxide mineral of strontium and boron. It has the composition SrB₆O₉(OH)₂.3H₂O. This sample is about 4x6 cm and is from Boron, California. It is described as tunellite with ulexite.