| Andalucite
is best known for its strong pleochroism
and it's unusual color which is
frequently a mixture of both red
and green. It isn't considered to
be a color change stone but it frequently
shows two colors, (red and green)
at the same time. Rough crystals
will often show green in one direction
and red in another. The color is
difficult to match on any any standard
color chart.
|
| Gemological
Information |
| Color
: |
Red
and Green |
| Refractive
Index: |
1.628
- 1.647 |
| Chemical
Composition: |
Al2SiO5 |
| Hardness: |
7
- 7.5 |
| Density: |
3.13
- 3.21 |
| Crystal
Group: |
Orthorhombic |
| Ocurrence: |
Brazil,
Sri Lanka, Spain, East Africa, Burma,
U.S.A. |
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