There are two minerals that have 3 directions of cleavage, not at 90 degrees (rhombohedral cleavage). Both will fizz in hydrochloric acid but one moreso than the other.
| Redily fizzes in acid | Click here |
| Fizzes slowly or not at all. Take a nail and powder the mineral. Drop some acid on the powder. It should now bubble more vigorously | Click here |
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| COLOR | STREAK | LUSTER | CLEAVAGE | HARDNESS | CRYSTAL SHAPE | SPECIFIC GRAVITY | OTHER PROPERTIES |