1911 Encyclopædia Britannica/Meerschaum

From Wikisource
Jump to navigation Jump to search

MEERSCHAUM, a German word designating a soft white mineral sometimes found floating on the Black Sea, and rather suggestive of sea-foam (Meerschaum), whence also the French name for the same substance, écume de mer. It was termed by E. F. Glocker sepiolite, in allusion to its remote resemblance to the “bone” of the sepia or cuttle-fish. Meerschaum is an opaque mineral of white, grey or cream colour, breaking with a conchoidal or fine earthy fracture, and occasionally though rarely, fibrous in texture. It can be readily scratched with the nail, its hardness being about 2. The specific gravity varies from 0.988 to 1.279, but the porosity of the mineral may lead to error. Meerschaum is a hydrous magnesium silicate, with the formula H4Mg2Si3O10, or Mg2Si3O8·2H2O.

Most of the meerschaum of commerce is obtained from Asia Minor, chiefly from the plain of Eski-Shehr, on the Haidar Pasha-Angora railway, where it occurs in irregular nodular masses, in alluvial deposits, which are extensively worked for its extraction. It is said that in this district there are 4000 shafts leading to horizontal galleries for extraction of the meerschaum. The principal workings are at Sepetdji-Odjaghi and Kemikdji-Odjaghi, about 20 m. S.E. of Eski-Shehr. The mineral is associated with magnetite (magnesium carbonate), the primitive source of both minerals being a serpentine. When first extracted the meerschaum is soft, but it hardens on exposure to solar heat or when dried in a warm room. Meerschaum is found also, though less abundantly, in Greece, as at Thebes, and in the islands of Euboea and Samos; it occurs also in serpentine at Hrubschitz near Kromau in Moravia. It is found to a limited extent at certain localities in France and Spain, and is known in Morocco. In the United States it occurs in serpentine in Pennsylvania (as at Nottingham, Chester county) and in South Carolina and Utah.

Meerschaum has occasionally been used as a substitute for soap and fuller’s earth, and it is said also as a building material; but its chief use is for tobacco-pipes and cigar-holders. The natural nodules are first scraped to remove the red earthy matrix, then dried, again scraped and polished with wax. The rudely shaped masses thus prepared are sent from the East to Vienna and other manufacturing centres, where they are turned and carved, smoothed with glass-paper and Dutch rushes, heated in wax or stearine, and finally polished with bone-ash, &c. Imitations are made in plaster of Paris and other preparations.

The soft, white, earthy mineral from Långbanshyttan, in Vermland, Sweden, known as Aphrodite (ἀφρός, foam), is closely related to meerschaum. It may be noted that meerschaum has sometimes been called magnetite (q.v.).