The authors recently examined four small marble-sized colorless polished spheres of rock crystal quartz. Each sphere hosted a tiny, opaque black inclusion (figure 1), a feature that was the subject of this entry. The spheres weighed between 3.07 and 10.53 ct, with corresponding measurements ranging from 7.61 to 11.49 mm. They were supplied by Luciana Barbosa of the Gemological Center in Asheville, North Carolina, and were reported to have come from Zambia.
As shown in figure 2, microscopic observation of the four polished spheres revealed that the opaque black inclusions were actually composed of numerous platy euhedral crystals arranged in the shape of a rose. These inclusions were identified by Raman analysis as hematite. The roses’ positioning along growth planes in the spheres shows that the hematite inclusions are syngenetic with their rock crystal quartz hosts.
The authors recently examined four small marble-sized colorless polished spheres of rock crystal quartz. Each sphere hosted a tiny, opaque black inclusion (figure 1), a feature that was the subject of this entry. The spheres weighed between 3.07 and 10.53 ct, with corresponding measurements ranging from 7.61 to 11.49 mm. They were supplied by Luciana Barbosa of the Gemological Center in Asheville, North Carolina, and were reported to have come from Zambia.
As shown in figure 2, microscopic observation of the four polished spheres revealed that the opaque black inclusions were actually composed of numerous platy euhedral crystals arranged in the shape of a rose. These inclusions were identified by Raman analysis as hematite. The roses’ positioning along growth planes in the spheres shows that the hematite inclusions are syngenetic with their rock crystal quartz hosts.
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