EXAMINATION OF MINERALS FOR GOLD.

Thames Star, Volume VII, Issue 1925, 5 March 1875, Page 2

EXAMINATION OF MINERALS FOR GOLD.

■: •. In answer: tor the question of-a Torres-, porident in a former issue; "Mi* L. Marks, Jecturer and ..teacher, of chemistry, School of Mme^rSaiidhLnwt, kindljrsenda thefollowing note.s.{f-«: John MiJne" (Casllemaine) may proceed as follows, being one of several methods e*sy of . application :->ln a Copperedbottle; iold- j ing 30z., place one fluid oz. of mine acid, c and 2oz. of hydrochloric acid ; r Jet aside, well closed, and labelled, "Aqa* Eegia," or " Nitro-bydrochloric Acid?' -In a tea-, cup, OTi others-suitable. vesseli?Jplace some: clean iron turnings^,or smail nails, andj' pour over them, say 6oz. of water, then) add loz. of sulphuric acid, aroid the • fpirtingg .ijfhich gr«M;;he|itejevolTed may give rise to, and set the^yessel aside uncovered until- the eflfervtscence has ceased; i'decant the solution, or fitter through paper, and. Mt^ifjde^a-vtnii" place until crystals have formed • remove them to white"^ blotting-paper to dry, and preserve in: a> fwellicloseili flry 1;. fettle, Jabelling it f;^.Sulphate'. of Iron.": (If more convenientjhis reagent may, b« purchased at a druggist's.) - Powdier.;the quartz suspected to contain gold, and placing a portion in a tali wineglass, pour in a sufficiency of the mixed acids,', end allow it to digest foi^someibours ; decant the clear liquid into a tall champagne fclass—or, preferably, into a saucer—and gently heat it for about a quarter of an hour. Dissolve some of the green crystals of sulphate, .of iron in water, and filter. through paper if npt .quits, bright; add the 'filtrate to the acid' solution, and set aside for 24 hours. The brown powder that ■ subsides is metallic* gold in a highly divided condition, and all but absolutely pure ; its quantity may be ascertained if . a (delicate balance is obtainable.—Australasian. - *:.