PART II.

OCCURRENCE OF ALUMINIUM IN NATURE.

THERE is no other metal on the earth which is so widely scattered and occurs in such abundance.

Al is not found metallic. Stocker* made the statement that Al occurred as shining scales in an alumina formation at St. Austel, near Cornwall, but he was in error. But the combinations of Al with oxygen, the alkalies, fluorine, silicon, and the acids, etc., are so numerous and occur so abundantly as not only to form mountain masses, but to be also the bases of soils and clays. Especially numerous are the combinations with Si and other bases, which, in the form of felspar and mica, mixed with quartz, form granite. Mierzinski gives the formulæ of a few of these silicates as:

These combinations, by the influence of the atmosphere, air, and water, are decomposed, the alkali is replaced or carried away, and the residues form clays. The clays form soils, and thus the surface of the earth becomes porous to water and fruitful. It is a curious fact that Al has never been found in animals or plants, which would seem to show that it is not necessary to their growth, and perhaps would act injuriously, if it were present, by its influence on the other materials. Most of the Al compounds appear dull and disagreeable, such as felspar, mica, pigments, gneiss, amphibole, porphyry, eurite, trachyte, etc.; yet there are others possessing extraordinary lustre, and so beautiful as to be classed as precious stones. Some of these,

with their formulæ, are

One would suppose that since aluminium occurs in such abundance over the whole earth, since we literally tread it under foot, that it would be extracted and applied to numberless uses, being made as abundant and useful as iron; but such is not the case.

Beauxite and cryolite are the minerals most used for producing aluminium, and their preference lies mainly in their purity. Native alums generally contain Fe, which must be removed by expensive processes. Some observations on a native alum deposited in New Mexico will be found in the Appendix. We will here consider at greater length only beauxite and cryolite.

BEAUXITE.

Beauxite is a combination between diaspor, A1203.3H2O, and brown hematite, Fe2O3.3H2O; or, it is diaspor with Al replaced more or less by Fe; the larger the amount of Fe the more its color changes from white to brown. It was first found in France, near the town of Beaux, large deposits occurring in the departments Var and Bouches du Rhon, extending from Tarascon to Antibes. Several of these beds are a dozen yards thick, and 160 kilometres in length. Deposits are also found in the departments of l'Herault and l'Arriège. Very important beds are found in Styria, at Wochein, and at Freibriss, in Austria, a newly discovered

locality where the mineral is called Wocheinite. Here it has a dense, earthy structure, while that of France is conglomerate or oölitic. Deposits similar to those of France are found in Ireland at Irish Hill, Straid, and Glenravel. Further deposits are found in Hadamar in Hesse, at Klein-Steinheim, Langsdorff, and in French Guiana.

The following analyses give an idea of the peculiar composition of this mineral; besides the ingredients given there are also traces of CaO, MgO, SO3, P2O3, TiO2, and Va2O3.

Index:

a and b. from Beaux (Deville).

C.

d.

e.

f.

g.

h.

i.

k.

1.

dark

light

}Wocheinite (Drechsler).

red brown

yellow
white

Beauxite from Feisstritz (Schnitzer).

white Wocheinite (L. Mayer and O. Wagner).
Beauxite from Irish Hill.

66

66

Glenravel (F. Hodges).
Hadamar (Hesse) (Retzlaff).

from Klein-Steinheim (Bischof).

p and q. from Langsdorff (I. Lang).

7.

Beauxite from Dublin, Ireland, brought to the Laurel Hill Chemical Works, Brooklyn, L. I., and there used for making alums. It is dirty white, hard, dense, compact, and in addition to the ingredients given above contains 0.59 per cent. CaO, and some TiO2. It costs $6 per ton laid down in the works. The above analysis, made by Mr. Joüet, is furnished me by the kindness of the superintendent of the works, Mr. Herreshoff.

As is seen from the above analyses, the percentage of Al2O3 is very variable, and cannot be determined at all simply by inspection but only by an analysis, for often the best-looking specimens are the lowest in A1203. For instance, a beauxite containing 62.10 Al2O3, 6.11 Fe2O3, 5.06 SiO2, and 20.83 H2O was much darker and more impure looking than that from Wochein (h) which contained only 29.8 per cent. A1203.