Black star diopside 2.79ct 9x7mm oval cabochon

A clean, well-proportioned oval black cabochon showing a crisp four-ray star centered neatly on the dome. The star arms are golden-bronze and cross at a precise central point, producing a balanced and even cross across the polished black surface. The stone has a very even, deep black body color with no visible grain or surface marks.

The four-ray star belongs to a class of optical effects known as asterism, produced when a gem contains fine needle inclusions arranged in two or more crossing directions that scatter light into visible rays across a polished dome. Diopside from Africa carries two such sets of rutile needles intersecting at right angles, which is why its star has four arms rather than six. The stone is untreated.

• Stone type: Natural diopside
• Weight: 2.79 ct
• Size: 8.9x7.1 mm
• Color: Black
• Phenomenon: Asterism (4-ray star)
• Cut: Oval cabochon
• Clarity: Opaque
• Treatment: Untreated
• Origin: Africa
• Hardness: 5.5-6 (Mohs)

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