MINERAL PROPERTIES: PERCUSSION FIGURE
A percussion figure is a flat, six-rayed "star" formed when hexagonal micaceous minerals are put under pressure.
The "star" is composed of six lines protruding from each corner of the crystal
that bisect near the center of the crystal. A percussion figure seen on a mineral proves
it to be a mica or related mineral. Pushing
a thin needle into the center of the crystals may artificially create percussion figures.
This will only work if the crystal meets the following criteria:
- Is hexagonal shaped
- Has a smooth, flat surface
- Has no flaws or cracks
