This semi-translucent black stone sometimes goes by the rather grandiose trade-name of 'Black Star of India', which refers to the fact that India is the most common source for this stone. It comes with a dark green to black bodycolour, typically- and rather unusually - showing a four-rayed star. Most stones with asterism show a 6-rayed star. The star usually has one sharp ray and one diffuse, and as with most star gems, the star is created by intersecting needles. In star diopside, the star is like this because the needles do not intersect at perfect right angles. It could be said to hide its light under a bit of a bushel, as the star is often not visible without some kind of overhead lighting. It should be noted that in the pictures of my stones, they are lit from above to demonstrate the star. It's a nice option for a black stone if you don't want something dyed like onyx, and it does have its fascinating secret asterism.