Recently, the author examined a 3.18 ct bicolor yellow and blue-green basalt-related sapphire that was mined in southern Vietnam. Under brightfield illumination, the stone revealed partially healed fissures exhibiting an intriguing Star of David pattern matching the pinacoid face (see above).
This type of fissure often displays a geometric crystal structure, resembling either a hexagon or a triangle, when perpendicular to the c-axis. However, the pattern of interlocking triangles is rarely observed. These unique triangles probably resulted from defects in the crystal structure, which arose during oscillating growth between the rhombohedral and pinacoidal planes. The partial healing process made these features noticeable under the microscope.
Recently, the author examined a 3.18 ct bicolor yellow and blue-green basalt-related sapphire that was mined in southern Vietnam. Under brightfield illumination, the stone revealed partially healed fissures exhibiting an intriguing Star of David pattern matching the pinacoid face (see above).
This type of fissure often displays a geometric crystal structure, resembling either a hexagon or a triangle, when perpendicular to the c-axis. However, the pattern of interlocking triangles is rarely observed. These unique triangles probably resulted from defects in the crystal structure, which arose during oscillating growth between the rhombohedral and pinacoidal planes. The partial healing process made these features noticeable under the microscope.
