Both of these copper minerals occur side by side with the titano-silicates.

Some of the drusy surfaces are coated with green or bluish green amphibole needles, and the natrolite and albite crystals often carry them in sufficient quantity to give a greenish or bluish tint. These amphiboles vary from place to place and even the same needle may show different optical properties along its length.

A common type is actinolite. This has been observed in thin needles growing out into open spaces as a newly formed mineral in the wall rock and in veins. Occasionally it develops as asbestos films or exceedingly fine hair-like bunches. It shows pleochroism in pale green and yellow, the c sometimes having a bluish tint. It gives a distinct sodium reaction in the blowpipe flame.

Another common amphibole is bluish green in color and shows under the microscope a greenish yellow, b gray violet, c bluish green. The axial plane is transverse to the plane of symmetry and the dispersion is so great that it shows no extinction in plane (010) with white light. The extinction for red light is about 25°30², for violet some 5° greater. Its properties would indicate a soda amphibole with considerable iron in the molecule -- perhaps intermediate between crossite and crocidolite, but nearer the crossite type.

A member of the glaueophane group is sometimes present. c blue, b violet, a yellow; c ^ c about 8°.

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