The mica group of sheet silicate (phyllosilicate) minerals includes several closely related materials having nearly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition. The nearly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms.
The word mica is derived from the Latin word mica, meaning a crumb, and probably influenced by micare, to glitter.
Chemically, micas can be given the general formula
in which
Structurally, micas can be classed as dioctahedral (Y = 4) and trioctahedral (Y = 6). If the X ion is K or Na, the mica is a common mica, whereas if the X ion is Ca, the mica is classed as a brittle mica.
Common micas:
Brittle micas:
Very fine-grained micas, which typically show more variation in ion and water content, are informally termed "clay micas". They include:
Mica and similar may refer to:
Tevita Fifita (born May 7, 1983) is a Tongan-American professional wrestler better known by his ring name Micah while his status with TNA is unknown. He is best known for working for WWE under the name Camacho between 2011 and 2014. He previously worked in WWE's developmental territory, Florida Championship Wrestling, under the name Donny Marlow where he was a one-time FCW Florida Tag Team Champion with CJ Parker. Part of a large wrestling family, he is the cousin of Bad Luck Fale, adoptive brother of Tama Tonga, and the son of Haku.
Born in Kissimmee, Florida, Fifita attended the University of Texas at El Paso [UTEP], where he played football as a defensive end. And graduated with a degree in Liberal Arts with major in Communications Electronic Media and minor in criminal justice.
On February 10, 2009, Fifita signed a developmental contract with World Wrestling Entertainment and was assigned to its developmental territory Florida Championship Wrestling (FCW) as "Tonga". In March, he became known as Agent T., as part of Washington's Secret Service stable alongside Agent D. and Agent C, He later changed his name to Donny Marlow. On July 21, 2011, Marlow and CJ Parker defeated Calvin Raines and Big E. Langston to win the FCW Florida Tag Team Championship. On November 3, Marlow and Parker lost the Tag Team Championship to Brad Maddox and Briley Pierce.