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Small quantities of this beautiful mineral have been found in Shaft No. 2, in a small bed of but a few square feet in area, but quite thick and appearing much like natrolite. This bed was about one hundred feet east from Shaft No. 2, and in the center of the heading when it was at that point.
There is, however, a very fine vein of pectolite about twenty-five feet further east from the natrolite bed; it runs from the floor to ceiling, and is about two inches in thickness; some specimens of which I took from these were unusually unique in both size and appearance.
There need be no difficulty in finding this vein if these conditions are carefully considered, or if one of the miners be asked as to the soft vein. Their specific gravity is 2.6, or near it, and hardness about 3, or equal to ordinary unpolished white marble. Natrolite.
Natrolite resembles stilbite, but may be distinguished by gelatinizing readily with hydrochloric acid and by not intumescing when heated before the blowpipe; from the other minerals by the form of the crystals and their setting, also the locality in the tunnel in which it was found.
Copper pyrites, by its aspect from the other minerals, and from iron pyrites by its inferior hardness and less gravity. Stilbite is characterized by its form, difficult gelatinizing, and intumescence before the blowpipe; from natrolite as mentioned under that species. Laumonite is known by its generally chalky appearance and a probable failure in finding it.
Pectolite sometimes resembles some of the others, but may be readily distinguished by its tough long fibers, not brittle like natrolite. Datholite may generally be distinguished by the form of its crystals and their glassy appearance, with great hardness, and by tingeing the flame from the blowpipe of a true green color.
Among them the species Analcime, Stilbite, Natrolite, and Chabazite may be mentioned as of most common occurrence. The microscope has shown that pure quartz is oftener present in lavas than was formerly supposed.
This is readily found, but is no distinction; its reaction before the blowpipe, however, is characteristic, it readily fusing to a transparent globule, clear and glassy, and by forming a jelly when heated with acids. The bed holding the upright crystals is also natrolite in confused matted masses. This mineral has also been found in other parts of the shaft, but only in small druses.
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