Potash Feldspal
Typically off-white or shades of red, orange and brown, occasionally green. .
One perfect cleavage and one good cleavage that meet at nearly 90°
It reflects the minerals’ abundance, as most crystalline material found in the field.
The potassium feldspar group is composed of three mineral having the same composition.
Other minerals in the rock to determine the host rock’s identity is often the most useful guide to identity.
The crystal structure of the plagioclase and potassium feldspar groups are so similar.
Potash Feldspal
One of the most important materials for medium and high temperature ceramic glazes. Potash feldspars are often not as pure and white as soda spars. A feldspar is typically referred to as ‘potash’ if there is significantly more potassium than sodium (typically there will be 2-5% Na2O). If the amounts are closer to equal they are termed potash-soda feldspars (or vice versa). Of course, real potash feldspars also have small amounts of CaO, MgO, Fe2O3, etc.
