Formula: Mg₃(Si₂O₅)(OH)₄

Species:

Colour: Green, green-blue, white, brown, black

Lustre: Vitreous

Hardness: 3½ – 4

Specific Gravity: 2.5 – 2.6

Crystal System: Monoclinic

Member of: Serpentine Subgroup > Kaolinite-Serpentine Group. Antigorite is a high-temperature serpentine mineral, forming only above 250°C. chrysotile and lizardite which are low-temperature serpentine minerals. Antigorite is not the most common serpentine mineral, although it is a common member of the group. Volumetrically, lizardite is the most abundant serpentine mineral.

Name: Named in 1840 by Mathias Eduard Schweizer for the type locality, Valle di Antigorio, Domodossola, Piedmont, Italy, although there is a small question if he were on the Italian side of the border.

Co-Type Localities: Antigorio Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy. Geisspfad area, Binn, Goms, Valais – Switzerland