|Derivation:||From "stauros lithos" (Greek) cross stone|
|Description:||Brown opaque crystals in a blade form (on the left of the photograph). You often get "twinning" where two crystals cross over. If this is at right angles (top right), then you get a cross shape. The bottom specimen is twinned but not at right angles.|
These are twinned crystals, which forms a cross where they meet.
Here, the crystals have not met at a right angle.