This is the picture jasper necklace. Length 16.5″ (42cm). Weight – 2.2oz (61 grams). Origin: Russia, Siberia.
Some information about jasper:
Jasper, an aggregate of microgranular quartz and/or chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron inclusions.
The specific gravity of jasper is typically 2.5 to 2.9. Along with heliotrope (bloodstone), jasper (green with red spots) is one of the traditional birthstones for March.
Jasper is an opaque rock of virtually any color stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica rich sediment or volcanic ash. Hydrothermal circulation is generally thought to be required in the formation of jasper.