Black star diopside 2.90ct 9x7mm oval cabochon

A neat oval cabochon in deep opaque black with a well-defined four-ray star displayed clearly across its surface. The star's arms are rendered in warm golden-bronze and converge at a distinct intersection point near the center of the dome, producing a balanced, even cross. The stone has a smooth, highly polished surface and very even black body color throughout.

The luminous cross on this stone is the result of a phenomenon called asterism, where parallel arrays of microscopic needle inclusions within a crystal align in multiple directions and collectively scatter light into a star pattern across the surface of a polished cabochon. In diopside, the four-ray star forms because rutile needle inclusions occur in two orientations at 90 degrees to each other, creating the characteristic plus-sign cross. The stone is untreated.

• Stone type: Natural diopside
• Weight: 2.90 ct
• Size: 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.