Page "Mineral" Paragraph 57

Cyclosilicates, or ring silicates, have a ratio of silicon to oxygen of 1: 3.

Six-member rings are most common, with a base structure of < sup > 12 -</ sup >; examples include the tourmaline group and beryl.

Other ring structures exist, with 3, 4, 8, 9, 12 having been described.

Cyclosilicates tend to be strong, with elongated, striated crystals.