Polyhalite Enlarge
[Undated]
Exotic Mineralogy
CXLVII
Calx Polyhalites

Polyhalite

  • Syn.
    • Polyhalite. Stromeyer in Schweiggers Journal, 21, 297 et seq. see Thompson’s Annals 13, 112.
    • Fibrous Anhydrite. Jameson, ed 2. vol. II. p. 249.
    • Fasriger Muriacite. Werner.

A recent account of this mineral has been published in the following translation of part of a letter from Professor Stromoyer, as quoted above, by Dr. Thompson:

“I shall conclude this letter by informing you of a new mineral, very remarkable, on account of its composition. I have given it the name Polyhalite. According to my analysis, 100 parts of it contain the following ingredients:

Hydrous Sulhate of Lime 28.74
Anhydrous Sulphate of Lime 22.36
Sulphate of Potash 27.48
Anhydrous Sulphate of Magnesia 20.11
Common Salt 0.19
Oxide of Iron 0.32
99.20

“This mineral occurs in the beds of rock salt at Ischel, in Upper Austria, and has been hitherto erroneously considered by mineralogists as Muriacite; and under the name of fibrous muriacite, it has been described as a variety of that mineral substance.”

The characters by which it may be recognized are its partial solubility in water, a hardness superior to Fibrous Gypsum; also a greater specific gravity, and a compact fibrous structure; between the teeth it feels rather gritty: it is nearly tasteless. When fresh broken it has a shining, slightly pearly surface, which becomes dull and rather whiter by exposure. Its fibres penetrate both ways into the Muriate of Soda, which serves for its matrix; they are of a dull red in the middle, and yellow brown at their extremities. The salt in which they are imbedded is white.

Close-up of poster Get a poster »