Art. IV. On the Tourmalines and other Minerals found at Chesterfield and Goshen, Massachusetts.
Art. IV. On the Tourmalines and other Minerals found at Chesterfield and Goshen, Massachusetts, by Col. George Gibbs.
(For the American Journal of Science.)
The schorl of the mineralogists of the last century united a variety of substances which subsequent observations have separated into several species. The green schorl is now the epidote, or the Vesuvian, or the actynolite. The violet schorl, and the lenticular schorl, are the axinite. The black volcanic schorl is the augite. The white Vesuvian schorl is the sommite. The white grenatiform is the leucite. The white prismatic is the pycnite, a species of the topaz, and another is a variety of feldspar. Of the blue schorl, one variety is the oxyd of titanium, another the sappare, and another the phosphate of iron. The schorl cruciform is the granatite. The octahedral schorl is the octahedrite, or anatase. The red schorl of Hungary, and the purple of Madagascar, are varieties of the oxyd of titanium. The spathique schorl is the spodumen.
The black schorl, and the electric schorl, only remained, and to avoid the confusion created by the use of the term schorl, the name of tourmaline was given to this species by that celebrated mineralogist, the Abbé Haüy.[50]
The tourmaline is found of almost every colour, and this variety of colour caused at first a number to be formed into new species; which are now considered only as varieties of the tourmaline: such as the rubellite, the tourmaline apyre, and indicolite.
The different analyses of the tourmaline, however, affords a greater variety of results than is known in almost any other mineral.
| The specific gravity of the | black varies | from 3.08 to 3.36 |
| Green | from 3.15 to 3.36 | |
| Red | from 2.87 to 3.10 |