Chemical Formula and Mineral Composition

SiO2

Silicon dioxide

Quartz, also known as SiO2 (silicon dioxide), is a silicate

Silicon	46.74 %
Oxygen	53.26 %

The Silicate class is the largest and most interesting class of all the classes. It is devided into groups based on mineral structures: Nesosilicates (single tetrahedrons), Sorosilicates (double tetrahedrons) , Inosilicates (single and double chains), Cyclosilicates (rings), Phyllosilicates (sheets), Tectosilicates (frameworks.) Quartz is a Tectosilicate. Then there are the members of the tectosilicate subclass: The Feldspar Group, The Feldspathoid Group, The Quartz Group, and The Zeolite Group. As you might assume quartz is part of the Quartz Group. All of the minerals in this group are made of SiO2. They do not all share the same properties but are still made of the same thing.

They are: Coesite Cristobalite Beta Cristobalite Keatite Beta Quartz Stishovite Tridymite Beta Tridymite Opal (sometimes concidered part of this group)

Opal