Black star diopside 4.13ct 9.1mm round cabochon

The largest round cabochon in this group at 4.13ct, this black diopside shows a four-ray star with natural character and a high dome that gives the cross a good three-dimensional presence when the stone is tilted. One arm of the star shows some disruption from natural inclusion material within the crystal, and the surface carries a few natural texture lines consistent with diopside's crystal character. Opaque jet-black body color overall with a mirror polish.

Asterism is the term for the moving star of light that appears on a polished cabochon surface when the gem's interior contains fine needle inclusions aligned in specific crystallographic directions. In black star diopside from Africa, two intersecting sets of rutile needles generate the four-ray cross, and the character and width of the star arms naturally depends on the density and distribution of those inclusions within each individual stone. No treatment of any kind has been applied.

• Stone type: Natural diopside
• Weight: 4.13 ct
• Size: 9.1 mm
• Color: Black
• Phenomenon: Asterism (4-ray star)
• Cut: Round cabochon
• Clarity: Opaque
• Treatment: Untreated
• Origin: Africa
• Hardness: 5.5-6 (Mohs)

Natural black star diopside, untreated, asterism, sold loose.