Crystal habit
defined as the size and shape of the mineral crystals and the structure or form shown by the mineral aggregates.
Luster
is the appearance of the mineral in reflected light.
Streak
is the color of a mineral powder. It is more consistent and reliable than the color of the mineral in the hand specimen.
Color
is due to the interplay between absorption, reflection, refraction and transmission of certain wavelengths of light that gives the color seen by the observer.
Cleavage
are the weak flat planes, along which the mineral can easily break. This is because of weak bonds along that direction which has more tendency to break.
mineral
is a naturally occurring solid material with an orderly crystalline structure and a definite chemical composition.