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University of California Publications. 



[Geology 



rine blue, i) = pale violet, 8 — gray yellow. (Fig. 7.) Some 

 lamellae of glaucophane with intense colors are almost uniaxial. 



In another section (II. 6.) besides a glaucophane with C = 

 azure blue, b — purple violet, a = yellow to colorless, y — fi = 

 0.002, 2 V large, we find a greenish amphibole with patches of 

 glaucophane. Pleochroism C = i) = greenish, a = colorless. 

 Birefringence weak; 2 V very small; positive; axial plane (010) ; 

 ext. (C:c) = -48? 



1 



Fig. 7. — Glaucophane crystal, g, with patches of karinthine, k, quartz, q, 



X30. 



Quartzite. — San Luis Obispo. II. 12. Becrystallized quartz 

 in some zones undisturbed, in others crushed. Garnet, titanite, 

 spinel grown also in glaucophane. Glaucophane with variable 

 colors, some lamellae rising up to those of the crossite. Angle of 

 the optic axis varying inversely to the intensity of the color. 



Gneiss. — Belmont School, Belmont. II. 17. Garnet, ilme- 

 nite with hematite, rutile with leucoxene, much musovite. Glau- 

 cophane in radical lamellae with very weak absorption ; angle of 

 extinction very small ; 2 V large ; negative. 



Quartzite. — Oak Hill, San Jose. II. 20. Idioblastic quartz, 

 garnet inclosed in glaucophane ; rutile and titanite in beautiful 

 crystals; muscovite (paragonite?), lawsonite. Glaucophane with 

 intense colors ; 2 V very small ; in some ultramarine lamellae al- 

 most uniaxial. Muscovite with rutile inclosed in glaucophane. 



Mica schist. — Calaveras Valley. II. 22. Brown garnet in- 

 closed in glaucophane ; little muscovite. Glaucophane with in- 

 tense colors and strong absorption; C = ultramarine blue, b — 

 purple violet, a = yellowish green; ext. angle very small; y — « 

 = 0.021 ; y — /3 — 0.005 ca. 2 V very small, negative ; axial 

 plane (010). 



