Orginating from many places including Russia, Kenya, Sri Lanka, Italy, Canada...the ones you will see currently in gemwow are from Myanmar and perhaps a few from India. The chemical formula is CaMgSi2O6. Forms in the monoclinic system. Hardeness is 5.5-6.5. One perfect directional cleavage, fracture is uneven to conchoidal. You will find the "star" variety in rings. The "star" are usually a little weak and have "diffused" lines. There is the chrome variety form Kenya and Russia. The best quality is purported to be from Myanmar.