ANT

ANT

( 61 )

This mineral in its crystalline form ap-proaches very near to felspar, and in its analysisdiffers only in containing an excess of alumine;to this excess its hardness and infusibility areno doubt to be attributed. It was the opinionof Count Bournon (and M. Hauy seems in-clined to agree with him) that andalusite isfelspar intimately mixed with corundum.

It occurs in granite in Spain, France, Saxony ,Ireland , and Devonshire.

ANTHOPIi Y LLITE.

This mineral has a perfectly foliated struc-ture, and though not crystallized, is divisible inthe direction of its natural joints, parallel tothe sides of a rectangular prism ; two of thesesections pre’sent brightly shining surfaces, andare much more easily obtained than the others.Besides these four joints two others may beperceived on close inspection with' a brightlight, dividing the prism diagonally. Its specificgravity is 3.2. Its hardness is about equal tothat of glass. Its colour is brownish, with moreor less of a pseudo-metallic lustre. It affordsby analysis,, according to M. Jqhn,

62.66 silex13.33 alumine4.0 magnesia12.0 oxide of iron3.25 oxide of manganese1.43 water

96.67

ANTIMONY,

§ 1. Ores of.

Red Antimony.

This substance was supposed to be a nativekermes or hydrosulphuret of antimony, but,according to a recent analysis by Klaproth, * itaffords

67.5 antimony10.8 oxygen19.7 sulphur

98.0

Native Antimony.

A specimen of this substance from Andreas—berg in the Hartz, has been analysed by Klap-roth , 6 with the following result:

9fj. antimonyI. silver0.23 iron

White Antimony.

A specimen of this mineral in quadrilateraltabular crystals, from Przibram in Bohemia ,was analysed by Klaproth, ' with the especialobject of ascertaining whether it contained anymuriatic acid as had been suspected bv Hac-quet. For this purpose 25 grs. of the mineralwere fused with 200 grs. of carbonated potash:the mass was then digested in water and thealkali was supersatuturated by nitric acid. ■ Onthe addition of nitrate of silver no precipitationtook place, hence the white antimony may beconsidered as a pure oxide of antimony.

Antimony with Nickel,

This ore has hitherto been found only in a'mine at Treusberg in Nassau / 1 It is composedin part of broad parallel plates of a shiningwhite, resembling antimony, and in part of acompact leaden grey substance with a glim-mering lustre. Its sp. gr. is 5.65. Its hardnessis superior to that of grey antimony. Whenexposed on charcoal to the action of the blow-pipe it melts readily, and disengages whitevapours of an arsenical odour, and which moreor less adhere to the charcoal in form of a yel-lowish powder; by degrees the globule becomesless fusible, and there remains behind a whitebrittle refractory button.

By digestion in nitric acid a portion of the oreis converted into a yellowish white voluminouspowder, and the remainder combines with themenstruum into a green liquor.

The powder, by digestion in muriatic acidslowly dissolves, with the-exception of a smallresidue of. a yellowish colour which consists ofsulphur, of sand, and of a little arseniate ofiron. This solution when diluted with waterlets fall a white precipitate consisting of muriate-of antimony and oxide of arsenic, inseparablefrom each other with perfect accuracy, accord-ing to Vauquelin, by any known chemical pro-cess, but in a considerable degree decomposable-by distillation with sulphur which raises the-principal part of the arsenic in the form of real-gar. What remains in the retort is sulphuretof antimony with a little arsenic and lead.

The green- nitric solution contains nickel,arsenic, and a little lead.

From the result of this examination, andfrom the different degree of fusibility exhibitedby different portions of the ore, it is considered,by Vauquelin as a mixture of sulphuret of an-timony, of arsenical nickel, a little galena and.,iron pyrites.

>>■ Ann. de Chim.kxxiii. p. 229. • Ann, (le Cllim, liXXV. p 20.'

4 Hau y tab. comp. 299. Kiap. Ess, ii. 142,

99.25

» Klapr. Ess. ii. 147,