Symud i'r prif gynnwys
Cuddio Rhestr Erthyglau

18 erthygl ar y dudalen hon

THE SYNTHESIS OF GEMS.

Newyddion
Dyfynnu
Rhannu

THE SYNTHESIS OF GEMS. In a German patent (D.R.-P. 182,200) a method is described for producing artificially certain mineral species, such as olivine, zir- con, beryll, a.nd spinelle, in a definitely ,erystiallin,e form. This consists in dissolving their constituent oxides in appropriate pro- portions in molten sodium or potassium meta- borate. The temperature of the fused mixture is then raised to 1,300deg. Cent., when the alkali metaborate volatilises, leaving the arti- ficial mineral in the form of crystals. In ad- dition to obtaining products corresponding wlill the naturally occurring minerals, other compounds having no iiiiiieralogical counter- parts may be produced by this method. A nickel chrome spinelle. prepared from its constituent oxides, was obtained in the form of small green crystals. It is well known that the mineral species corundum occurs in the form of very variously coloured stones rang- ing from colourless sapphire to brown and opaque corundum. Between these extremes one meets with sapphires tinted in yellow, green, blue, red. and intermediate hues, and it is generally supposed that these various colours are due to the presence of compounds of iron, manganese, chromium titanium or other foreign elements.

DENBIGH.!

A SCIENTIFIC WONDER.

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