Relief
when you look at thin sections, some minerals are clearly visible (details of surface texture, cleavage) while others appear almost featureless and, if
colourless, barely visible. This is the property associated with difference in refractive indicates -
n mostly between crystal and oil - Canada balsam and known as
relief.
If difference between mineral and surrounding is:
- large, the crystal is said to have a high relief
- slightly larger than the surrounding, it is called positive relief
- smaler - it is negative relief
