A (bio)molecule that serves as a catalyst for a chemical reaction.
A (bio)molecule that serves as a catalyst for a chemical reaction.
A trioctahedral member of the true mica group. The end-member formula is NaLiAl2(Al2Si2)O10(OH)2. Ephesite occurs as the 1M and 2M1 polytypes. Ephesite has been identified in pegmatite as a hydrothermal alteration product with analcime and natrolite from the Ilimaussaq intrusion, Greenland, and in manganese ore from Postmasburg, South Africa.
A poorly defined material, possibly an altered chlorite.
A poorly defined material, possibly a muscovite and K-rich feldspar pseudomorph after cordierite.
A poorly defined material, possibly illite.
An oriented crystalline overgrowth forming on a monocrystalline substrate. This overgrowth occurs when the lattice dimensions within the common plane of the overgrowth and the substrate are similar. For moderate differences, dimensional variations of the two phases may still result in a continuous contact. However, for larger differences in the lattices of the two phases, small particles may form of the overgrowth phase if only limited accommodation occurs.
The beginning of low-grade metamorphism. The epizone is defined by Kübler indices less than 0.25 in mudrock lithologies.
Cf., Kübler index
Symmetry equivalent points, which commonly refers to positions of symmetrically equivalent atoms in a crystal structure.
See equipoint.
Clay particles are often size-separated using Stokes’ law, although Stokes’ law applies strictly to spherical particles only. Clay particles with platy shapes settle at slower rates than spheres of equal density in a fluid, however. If Stokes’ law is used in the size-separation analysis, it is appropriate to describe the platy clay particle as settling at velocity equal to that of a sphere of “equivalent” diameter (equivalent spherical diameter or esd or e.s.d.).
See Stokes’ Law