page_title: Lawsonite
hierarchical_section_title: Lawsonite
caption_attribution_description: English: Lawsonite Locality: Reed Station, Tiburon Peninsula, Marin County, California, USA (Locality at mindat.org) Size: 6.1 x 3.2 x 2.5 cm. This specimen is from the type locality in California. It features two elongated, lustrous and translucent crystals of pastel pink, lawsonite, in crystals to 4.0 cm in length. This very rare species, embedded in a mica schist, is a calcium, aluminum silicate. Ex. John Ydren collection. Deutsch: Lawsonit Fundort: Reed Station, Tiburon Peninsula, Marin County, Kalifornien, Vereinigte Staaten (Fundort bei mindat.org) Größe: 6.1 x 3.2 x 2.5 cm.
context_page_description: Lawsonite is a hydrous calcium aluminium sorosilicate mineral with formula CaAl₂Si₂O₇(OH)₂·H₂O. Lawsonite crystallizes in the orthorhombic system in prismatic, often tabular crystals. Crystal twinning is common. It forms transparent to translucent colorless, white, and bluish to pinkish grey glassy to greasy crystals. Refractive indices are nα=1.665, nβ=1.672 - 1.676, and nγ=1.684 - 1.686. It is typically almost colorless in thin section, but some lawsonite is pleochroic from colorless to pale yellow to pale blue, depending on orientation. The mineral has a Mohs hardness of 8 and a specific gravity of 3.09. It has perfect cleavage in two directions and a brittle fracture.
  Lawsonite is a metamorphic mineral typical of the blueschist facies. It also occurs as a secondary mineral in altered gabbro and diorite. Associate minerals include epidote, titanite, glaucophane, garnet and quartz. It is an uncommon constituent of eclogite.
  It was first described in 1895 for occurrences in the Tiburon peninsula, Marin County, California. It was named for geologist Andrew Lawson of the University of California by two of Lawson's graduate students, Charles Palache and Frederick Leslie Ransome.
context_section_description: Lawsonite is a hydrous calcium aluminium sorosilicate mineral with formula CaAl₂Si₂O₇(OH)₂·H₂O. Lawsonite crystallizes in the orthorhombic system in prismatic, often tabular crystals. Crystal twinning is common. It forms transparent to translucent colorless, white, and bluish to pinkish grey glassy to greasy crystals. Refractive indices are nα=1.665, nβ=1.672 - 1.676, and nγ=1.684 - 1.686. It is typically almost colorless in thin section, but some lawsonite is pleochroic from colorless to pale yellow to pale blue, depending on orientation. The mineral has a Mohs hardness of 8 and a specific gravity of 3.09. It has perfect cleavage in two directions and a brittle fracture.
  Lawsonite is a metamorphic mineral typical of the blueschist facies. It also occurs as a secondary mineral in altered gabbro and diorite. Associate minerals include epidote, titanite, glaucophane, garnet and quartz. It is an uncommon constituent of eclogite.
  It was first described in 1895 for occurrences in the Tiburon peninsula, Marin County, California. It was named for geologist Andrew Lawson (1861–1952) of the University of California by two of Lawson's graduate students, Charles Palache and Frederick Leslie Ransome.
caption: Sample from the type locality in California with two elongated, lustrous and translucent crystals of pastel pink, lawsonite in mica schist (size: 6.1 x 3.2 x 2.5 cm)
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