![](http://www.alamy.com/thumbs/6/DFD10C5F-F3E6-4F5E-8A3F-C6F414B01B5D/2ACWY8B.jpg)
Tourmaline crystals (green) in quartz. Tourmaline is a boron-silicate mineral that forms crystals that are straight elongate prisms. It occurs in a nu
Tourmaline crystals (green) in quartz. Tourmaline is a boron-silicate mineral that forms crystals that are straight elongate prisms. It occurs in a number of colours, some of which are much sought after as semi-precious gemstones. This specimen, from Minas Gerais, Brazil, is 120 millimetres wide.
Size: 5616px × 3744px
Photo credit: © DIRK WIERSMA/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: -, background, blue, boron, boron-silicate, crystal, crystalline, crystals, dioxide, gem, gemstone, geological, geology, mineral, mineralogy, quartz, rock, semi-precious, silicate, silicon, tourmaline, turmaline, verdelite