mountain soap
noun1
Obsolete, Possibly A soft earthy mineral, of a brownish colour, which has a greasy or soapy feel and is used as a filler in crayons.
- It soils either strongly, as chalk and mountain soap; or slightly, as molybdana, lead glauce, and graphite. Besides this, there are three other distinctions connected with this character to be attended to.1805, Robert Jameson, A Treatise on the External Characters of Minerals, page 76:
- […] seven different minerals possessing the same formula, namely, fahlunite, esmarkite, pyrargillite, bole, iron lithomarge, halloylite from La Vouth and from Thiviers, and mountain soap from Thuringia.1848, American Journal of Science and Arts, page 72:
1 more example
- Sometimes, after removing the coating of calcspar from the crystals, they appear to be covered with a mass resembling steinmark or mountain soap. The compact and crystalline hornblende occurs almost everywhere as a constituent of the[…]1859, Gustav Bischof, Elements of Chemical and Physical Geology ..., page 311: