Many other minerals are pleochroic however most have such a small color change that it is not noticable by the human eye. Other minerals such as elbaite, show stronger pleochroism where changes in color shading can be discerned. Only a few minerals such as cordierite and the zoisite variety called tanzanite are extremely pleochroic and it is very easy to see the color changes. The strong pleochroism is the reason that cordierite and iolite are sometimes referred to by the synonym dichroite a greek word meaning two colored rock. Although cordeirite is actually trichroic the dichroic name has persisted.
Color is typically blue, violet, gray, brownish or colorless.
Luster is vitreous. Transparency crystals are transparent to translucent. Crystal Habits include rare prismatic crystals but is usually massive, or in compact grains embedded in metamorphic schists and gneisses. Also found as pebbles and grains in alluvial deposits. Cleavage is poor in one direction.