serpentine A group of minerals belonging to the 1:1 group of phyllosilicates (sheet silicates) with the composition Mg₆ [Si₄O₁₀](OH)₈ and including the minerals chrysotile (the asbestiform variety), lizardite, and antigorite; sp. gr. 2.55–2.60; *hardness 2.0–3.5; monoclinic; chrysotile is fibrous whereas lizardite and antigorite occur as flat tabular crystals or massive; various shades of green, also brown, greywhite, or yellow; greasy to waxy lustre, occasionally silky; formed from altered olivine and orthopyroxene. It results from the alteration of ultramafic (see ULTRABASIC) rocks either by hydrothermal action at a late stage or by alteration during metamorphism, chrysotile forming first and then altering to antigorite; it is a constituent of ophicalcites, a serpentine-calcite rock derived from the dedolomitization (see DEDOLOMITE) of a siliceous dolomite. It is used extensively as a facing stone and for ornament; chrysotile has been used as a source of commercial asbestos in Thetford, Canada. Lizardite occurs on the Lizard Peninsula, Cornwall, UK.

ser·pen·tine / ˈsərpənˌtēn; -ˌtīn/ • adj. of or like a serpent or snake: serpentine coils. ∎  winding and twisting like a snake: serpentine country lanes. ∎  complex, cunning, or treacherous: his charm was too subtle and serpentine for me.• n. 1. a dark green mineral consisting of hydrated magnesium silicate, sometimes mottled or spotted like a snake's skin.2. a thing in the shape of a winding curve or line, in particular: ∎  a riding exercise consisting of a series of half-circles made alternately to right and left.3. hist. a kind of cannon, used esp. in the 15th and 16th centuries.• v. [intr.] move or lie in a winding path or line: fresh tire tracks serpentined back toward the hopper.

serpentine Group of sheet silicate minerals, hydrated magnesium silicate (Mg₃Si₂O₅(OH)₄). Serpentine minerals come in various colours, usually green, although sometimes brownish, with a pattern of green mottling. They have monoclinic system crystals. They are commonly used in decorative carving; fibrous varieties are used in asbestos cloth. Hardness 2.5–4; r.d. 2.5–2.6.