Silicate minerals form over 90 percent of Earth's crust, they contain silicon (Si) and oxygen (O). Silicates are further broken down into six categories based on the complexity of their structure. Phyllosilicates Phyllosilicates (sheet silicates) are based on each tetrahedron sharing three oxygen atoms with another, thus forming two-dimensional sheets. These silicates which form at low temperatures can be split easily. Micas and serpentines are examples.
