It forms red crusts, is insoluble in cold water, but is decomposed by boiling water.
The waters of Bahr-Assal are deeply impregnated with salt, which, in thick crusts, forms crescent-shaped round the banks - dazzling white when reflected by the sun.
This product melts at 86° C., and becomes anhydrous when heated to 110° C. The anhydrous compound can also be prepared, as hard crusts melting at 146°, by crystallizing concentrated aqueous solutions at 30 to 35°.
After a month or so the plates are converted to a more or less considerable depth into crusts of white lead.
Columbium trichloride, CbC1 3, is obtained in needles or crystalline crusts, when the vapour of the pentachloride is slowly passed through a red-hot tube.
It forms hard crystalline crusts (with 1H 2 0) made up of hard white needles.
It is deposited from water, which bubbles up from a number of springs in the form of horizontal layers, which at first are thin crusts and can easily be broken, but gradually solidify and harden into blocks with a thickness of 7 to 8 in.
The solid crusts found at the bottom of the salt lakes of the Araxes plain in Armenia contain about 16% of carbonate and 80 of sulphate.
About Szegedin in Hungary and all over the vast pusztas (steppes) between the Theiss and the Danube, and from the Theiss up to and beyond Debreczin, the soil contains sodium carbonate, which frequently assumes the form of crude alkaline crusts, called "szekso," and of small saline ponds.
In the next group of forms the simplest are crusts attached to the substratum throughout their extent, and growing at the margin.
The lake bed is for the most part clear sand along the margin, and in deeper water is largely coated with crusts of salt, soda and gypsum.
Flaking and scaling set in; hard crusts of mildew formed, dissolved and re-formed with changes of weather over both the loosened parts and those that remained firm.