Staurolite aka Fairy cross,fairy tears and cross stone.

It is associated with earth,water ,air and fire.
good luck, protection, security,astral connection, confidence. it's favored in magic. to balance the four elements within and it is placed on the altar for power during magickal rituals of all kinds.said to protect against negative energies, disease and accidents.believed to energize sexual drive and draw wealth

The Celtic story says it is the tears of the faeiries that crystalized when their circles were destroyed.

The Cherokee say they are left by Elohino (Mother Earth) for her children to use to stay in contact with the four elements of life.

different types:
St. Andrew. crosses symbolize the interpenetration of the physical and spirutal planes, the combination of projective and receptive energies within our bodies and souls. looks like the rune of Nyd

Roman:shaped more like a T

Maltese: this is a perfect cross and these are the most sought after. also this type was made into a wand.specifically a labadorite wand. for some ritual use.

also some people have problems keeping them. as they tend to disappear and re-appear for te bearer.