414 JULIEN 



pleochroic, reddish to colorless, with absorption deepest parallel 

 to fibration. Interference colors brilliant, like those of tremo- 

 lite, from yellow and deep red of First Order to sky-blue of 

 Second Order. Extinction parallel to fibration ; (; = r. In con- 

 vergent light, only obscure interference figure, the position of 

 whose axial plane was not determined. Double refraction posi- 

 tive. The scales are usually intersected by veinlets of colorless 

 serpentine in an open network with elongated interspaces, often 

 0.2 mm. in length, sometimes polygonal with five or six sides, 

 in a kind of islet network. 



Other scales, apparently of altered amphibole, resemble those 

 of bastite, and are generally o. 17-. 27 mm. in length, often color- 

 less, or greenish and pleochroic, and without relief. These also 

 possess an exceedingly fine fibration and occasionally show 

 cleavage traces in a columnar structure. Interference colors in 

 part like those of amphibole, in part bluish gray of First Order. 

 Extinction in selected spots perfect and parallel, but generally 

 irregular and imperfect, as in an aggregate of altered fibers, and 

 apparently parallel. 



Around these grains runs a border, 0.0 1 0-0.0 14 mm. in 

 width, made up of colorless granular tremolite, with marked 

 relief. Much of this is columnar or rod-like, and many rods 

 lie scattered around, as if loosened by movements. Minute 

 veinlets of tremolite also penetrate the grains of amphibole, and 

 granules lie here and there along its fibration. All the features 

 point to steps in the passage of the primary bronzite and its 

 bastitic derivatives into forms of amphibole, last of all into 

 secondary tremolite. 



Talc occurs in scattered blades, fibrous bundles and long 

 wisps resembling the sheaves of tremolite, presenting the usual, 

 brilliant interference colors, red, green, etc., of the Third Order. 

 Extinction parallel to the fibers. C || c. Jn convergent light, 

 the emergence of an optic axis, with a system of rings, some- 

 times appears. 



Chromite is scattered in jet-black angular grains of finely 

 granular texture and high lustre in reflected light, up to 0.3 to 

 I mm. in diameter. Many are irregular in form, rudely rhom- 



