- any member of a group of minerals, hydrous silicates of aluminum with other bases, chiefly potassium, magnesium, iron, and lithium, that separate readily into thin, tough, often transparent, and usually elastic laminae; isinglass.
- any of a group of lustrous rock-forming minerals consisting of hydrous silicates of aluminium, potassium, etc, in monoclinic crystalline form, occurring in igneous and metamorphic rock. Because of their resistance to electricity and heat they are used as dielectrics, in heating elements, etc
n.1706, from specialized use of Latin mica “crumb, bit, morsel, grain,” originally *smika (form probably influenced by Latin micare “to flash, glitter”), from PIE *smik- “small” (cf. Greek smikros, Attic mikros “small;” Old High German smahi “littleness”). Related: Micaceous “containing mica.”
- Any of a group of hydrous aluminosilicate minerals with the general formula (K,Na,Ca)(Mg,Fe,Li,Al)2-3(Al,Si)4O10(OH,F)2that can be split easily into thin, partly transparent sheets. Mica is common in igneous and metamorphic rocks and often occurs as flakes or sheets. It is highly resistant to heat and is used in electric fuses and other electrical equipment. Muscovite and biotite are types of mica