illite (hydromuscovite) Common clay mineral and important member of the 2:1 group of phyllosilicates (sheet silicates) with the formula K1−1.5 Al4[Si7−6.5 Al1−1.5 O20](OH)4, which possesses an overall negative charge due to incomplete charge balance; sp. gr. 2.6–2.9; hardness 1–2; monoclinic; crystals form tiny flakes; formed by the weathering decomposition or hydrothermal alteration of muscovite or feldspar.
More From encyclopedia.com
Al-aqsa Mosque , al-Aqṣā Mosque Aqṣā Mosque Al-kashi , Al-Kāsh Al-Kāshī (or Al-Kāshānī), Ghiyāth Al-Dīn Jamshīd Mas’ūd (b. Kāshān, Iran; d. Samarkand [now in Uzbek, U.S.S.R], 22 June 1429) astronomy, math… Ale , ale •ail, ale, assail, avail, bail, bale, bewail, brail, Braille, chain mail, countervail, curtail, dale, downscale, drail, dwale, entail, exhale, fa… Muhammad Ibn Abd Al-wahhab , Ibn ʿAbd al-Wahhāb, Muḥammad IBN ʿABD AL-WAHHĀB, MUḤAMMAD (ah 1115–1206/1703–1792 ce), Islamic fundamentalist teacher who established the Wahhābi mov… Al-battani , Al–Battani One of the most important astronomers and mathematicians of this time in either the Eastern or the Western world was al–Battani (c. 858–92… Salat , Ṣalāt. The ritual worship of the Muslim community. One of the five pillars of the faith, it is frequently mentioned in the Qurʾān as a duty. Believe…
About this article
Updated About encyclopedia.com content Print Article