Celestite

Pale blue clarity from sky and stillness.

Celestite, also called celestine, is a pale blue-to-clear strontium sulfate mineral that forms as delicate, glass-like crystals clustered inside geode cavities. The finest commercial celestite comes from Madagascar's Sakoany deposits. It is soft and fragile, and the pale blue color fades in direct sunlight, which is why care matters with this stone. Celestite is rarely treated in the market because the natural color is desirable and treatment would damage the fragile crystals. For more on what makes Madagascar such a generous geological source, read why one island punches above its weight in the crystal world.