Recently, diopside displaying asterism when the stone is cut en cabochon has been seen quite often on the market for minor gemstones.
Appearance This is generally a blackish or blackish green color; rarely a definite green. It is, of course, out into round or oval cabochons, which are generally biconvex with a roughly shaped, unpoiished base. The star characteristically has four rays, two of which are straight. while the other two, not at right angles to the first pair, look slightly wavy (the crystal does not, in fact, have fourfold symmetry). Sometimes, oriented acicular (needleiike) surface crystalline inclusions are clearly visible, especially from below.
Stones weighing several tens of carats are also found, but they are not normally cut so large, as this makes them hard to use.
Distinctive features Star diopside has only binary symmetry, and the star has four rays, rather than six like other star stones.
When the gem contains conspicuous needlelike crystals (of magnetite) it is easily attracted by a magnet.
Occurrence Star diopside comes mainly from india.
Value Very low, one of the lowest for gems, even though asterism always has a certain appeal.
Simulants and synthetics it is neither imitated nor produced synthetically. it is sometimes passed off as star sapphire, although the resemblance is highly superficial. given the obvious difference in asterism.