A faceted malachite doublet set in bead detailed sterling silver, with logo in 18K yellow gold. Imported. Sterling silver/malachite/clear quartz/18K yellow gold. 20Mm; 0.75" x 0.75" Size: 7. Almost all gemstones and black diamonds have been treated to enhance their beauty and require special care. Photo may have been enlarged and/or enhanced. Ring Size Chart.