Good crystals of jadeite, a few doubly terminated, have been discovered by Dr. John Peoples of Petaluma, California, along the Russian River near Cloverdale, California. Optical data: α = 1.640, β = 1.645, γ = 1.652, all ± 0.003; biaxial positive; 2V = 67°; elongation positive; nonpleochroic; extinction angle Z∧c = 40°; Y = b. Crystallographic data: a:b:c = 1.1026:1:0.6110; β = 107° 3812; Forms: b {010}, a {100}, i {130}, m {110}, y {101}, u {111}, s {111}, Δ {311}. Twin index, 1; obliquity, 1° 34′. X-ray data: a0 = 9.48, b0 = 8.59, c0 = 5.23 KX; β = 107° 26′; a0:b0:c0 = 1.104:1:0.609; space group C 2/c. Chemical analysis: indicates composition of 94% jadeite, 6% diopside.

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