Louderback, G. D. "Benitoite, Its Paragenesis and Mode of Occurrence." University of California Publications.
Page 361
To get a more definite idea of the chemical nature of the amphibole occurring in the druses carrying the perched natrolites, a separation was attempted. The material is essentially of the type just described as related to crossite, but contained a small amount of actinolitic and other amphibole material in spots and zones on the crystals, and also a very small amount of natrolite that could not be entire]y separated. Professor Blasdale's analysis follows:

*All Fe assumed to be ferrous.

Albite.

Albite has not been found in direct association with benitoite or neptunite. It is common in minute veins in some of the sur- rounding rock, where it is generally granular and determinable only by means of the microscope. But in places it is developed in druses in the zone of mineralization and appears as crystals 5 to 10 mm. long growing from the blue-green amphibole wall. These crystals are generally translucent grayish or greenish in hue, due to included amphibole fibres.

Most commonly the crystals are twinned according to the albite law. Simple twins are the rule, but sometimes there are several very thin polysynthetic lamellae intercalated between the two main halves of the twin. The habit is defined by the dominance of M, M (010); l,l (110); T, T (110); o,o (111); p, p (111) and P, P (001). The forms are named in order of size. M is the largest though never so large as to produce a distinctly tabular habit, T and o about the same, and P distinctly smallest. The general mode of growth is such that the crystals are attached

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