Stone: Black Onyx
Frame Material: 18K Gold Plated Over Solid Genuine .925 Sterling Silver.
Shape: Faceted teardrop shape on both sides.
Measurement: 18.5mm long 11.5mm wide, stone size is 10x14mm.
Weight: 2.5 grams per 2 pieces.
These stones are known as hydrothermal quartz, which contains the same physical, chemical and optical properties of a natural stone. Chalcedony and onyx stones are extremely similar to quartz with an opaque look. For further information and details regarding this process, see the Beadunion Blog: http://www.beadunion.com/bezel-gemstone-information