Tourmaline is the name given to a very chemically complex (A(D3)G6(Si6O18)(BO3)3X3Z) family of stones. With slight chemical differences it comes almost every colour varying from light to dark. All types of tourmaline form according to a hexagonal crystal system and have a hardness of 7.5 on the Mohs scales. These are considered precious stones and some varieties are highly valued.
Clear Quartz & Variations
Clear Quartz also known as Rock Crystal ranges from white (opaque) to clear (transparent), and belongs to the rock crystal family of stones. All rock crystals are composed of SiO2 They form according to a trigonal crystal structure, and have a hardness of 7 on the Mohs scale.