PETROGRAPHIC CHARACTERISTICS
OF UNKNOWN #1
| MATERIAL NAME |
|
| HABIT |
Rhombic to Irregular |
| COLOR AND PLEOCHROISM |
Colorless
|
| APPROXIMATE
R.I. VALUE |
Between 1.55 and 1.60 |
| INTERFERENCE COLORS |
High |
| EXTINCTION |
Not Applicable (Crystals are not elongate) |
|
ADDITIONAL DESCRIPTIVE FEATURES |
Commonly display parallel bands of color (twins) when observed under crossed-polars |
| KEY DIAGNOSTIC FEATURES |
Rhombic habit and high interference colors |