Hydromica

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Hydromica \Hy`dro*mi"ca\, n. [Hydro-, 1 + mica.] (Min.)
     A variety of potash mica containing water. It is less elastic
     than ordinary muscovite.
     [1913 Webster]
  
     {Hydromica schist} (Min.), a mica schist characterized by the


        presence of hydromica. It often has a silky luster and
        almost soapy feel.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Mica \Mi"ca\, n. [L. mica crumb, grain, particle; cf. F. mica.]
     (Min.)
     The name of a group of minerals characterized by highly
     perfect cleavage, so that they readily separate into very
     thin leaves, more or less elastic. They differ widely in
     composition, and vary in color from pale brown or yellow to
     green or black. The transparent forms are used in lanterns,
     the doors of stoves, etc., being popularly called
     {isinglass}. Formerly called also {cat-silver}, and
     {glimmer}.
     [1913 Webster]
  
     Note: The important species of the mica group are:
           {muscovite}, common or potash mica, pale brown or
           green, often silvery, including {damourite} (also
           called {hydromica} and {muscovy glass}); {biotite},
           iron-magnesia mica, dark brown, green, or black;
           {lepidomelane}, iron, mica, black; {phlogopite},
           magnesia mica, colorless, yellow, brown; {lepidolite},
           lithia mica, rose-red, lilac.
           [1913 Webster] Mica (usually muscovite, also biotite)
           is an essential constituent of granite, gneiss, and
           mica slate; {biotite} is common in many eruptive rocks;
           {phlogopite} in crystalline limestone and serpentine.
           [1913 Webster]
  
     {Mica diorite} (Min.), an eruptive rock allied to diorite but
        containing mica (biotite) instead of hornblende.
  
     {Mica powder}, a kind of dynamite containing fine scales of
        mica.
  
     {Mica schist}, {Mica slate} (Geol.), a schistose rock,
        consisting of mica and quartz with, usually, some
        feldspar.
        [1913 Webster]