Vol. 5] 



Eakle. — Lawsonite. 



83 



tified constituent he subsequently identifies as lawsonite and adds 

 that it occurs frequently in the glaucophane rocks of several val- 

 leys in the Piedmont Alps. 5 



Lacroix observed lawsonite in the rocks of Corsica and of New 

 Caledonia. The Corsican rock from the region about Bastia con- 

 tains large crystals of diallage partly changed to glaucophane and 

 actinolite, and surrounded by a greenish white mass which re- 

 solved itself into a mixture of lawsonite, albite, anorthite, chlo- 

 rite, actinolite, and epidote. In New Caledonia the gabbros from 

 the Diahot Valley consist of large unaltered crystals of diallage 

 surrounded by a schistose mass of glaucophane needles and many 

 distinct crystals and grains of lawsonite. 



Viola 7 mentions lawsonite as a constituent of the gabbro- 

 diabase-peridotite near the border between the compartments Ba- 

 silicata and Calabrie, in southern Italy. The labradorite and 

 bytownite feldspars of the diabases and gabbros have become 

 sausuritized into a mixture of albite, mica, quartz, epidote, and 

 lawsonite. He notes that when lawsonite is abundant epidote is 

 scarce, and conversely, thus calling attention to the similar role 

 of the two as metamorphic products. 



Occurrences in California, — Lawsonite as yet has not been 

 observed in this country outside of California. The type locality 

 described by Ransome is a region of actinolitic and glaucopha- 

 nitic schists. Much garnet occurs in the actinolitic schists, and 

 occasionally schistose and compact masses of chlorite are found, 

 presumably as an alteration of the actinolite-garnet rock. 



Lawsonite does not occur as a regularly disseminated constit- 

 uent of the regional schists, but is found sporadic, usually in 

 large amounts mixed with actinolite and glaucophane or with 

 chlorite, often forming boulcler-like masses. The crystals de- 

 scribed by Ransome occur in such a mass, consisting mainly of 

 actinolite and muscovite with smaller amounts of glaucophane, 

 epidote or zoisite, chlorite, and titanite. Some of the largest 

 crystals are imbedded in a greenish-gray mass of flaky muscovite 

 which forms a vein in the actinolitic mass. This micaceous min- 



5 Bull. Soc. Fr. Min., 1897, 20, 5-7. 

 Ibid., 309-312. 



7 Zeits. fiir Kryst., 1897, 28, 553-555. 



