Black Crystal Basalt Rock Gravel Central California quarry, this material ships in bulk to all major regions of Central and Northern California. Shipped in SuperEarth-sacks throughout California and where requested. One of 2 types of two types of black basalt rock in California, this rock features bold reflective crystals, like miniature black mirrors, that are especially strong in the 5/16" and 3/8" sizes. These little black mirrors sparkle in the sunlight and this material makes an excellent top end pathway or driveway material. This is the most true black rock sold in California, perhaps in the whole Southwest. Designers should be able to use this unique material to produce some great works. This bold black hard rock gravel material is sold as boulders, rip rap, gravel and crushed stone fines.