SatinCrystals Tourmaline Black Raw Gemstone Premium Protective Boulder Rock Chunk Crystal Power Stone P01 (2.25 Inches) This black boulder gemstone is made from genuine Tourmaline. It is solid with natural smooth surfaces intermixed with rocky rough surfaces and minerals. Tourmaline increases spiritual awareness. It is very protective and provides confidence. Limited Edition. Receive one unique stone from an elite hand selected Satin Crystals collection.