Red Chalcedony (likely dyed)

Hardness: 6.5-7 on Mohs scale; Color: Red (often artificially enhanced); Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline (fibrous aggregates of quartz); Cleavage: None (fractures conchoidally); Specific Gravity: 2.58-2.64

Chalcedony forms from aqueous solutions rich in silica, often precipitated in cavities of igneous and sedimentary rocks. It can form at low temperatures and pressures. Natural red chalcedony is rare and known as Carnelian or Sard, with its color due to iron oxides (hematite). The intense, uniform red in the image, combined with the 'Jade Calcedoine' label (which often refers to dyed chalcedony or quartz that mimics jade), strongly suggests artificial dying. Geological age varies depending on the specific deposit, ranging from ancient to relatively recent.

Primarily used in jewelry for beads, cabochons, and carvings due to its attractive color (especially when dyed or naturally occurring as Carnelian/Sard), durability, and ease of polishing. It is also used in ornamental objects. Dyed chalcedony provides an affordable alternative to rarer gemstones.

The term 'chalcedony' is a broad category encompassing various microcrystalline quartz varieties, including agate, carnelian, onyx, and jasper. Natural red chalcedony, known as Carnelian (or Sard for darker shades), has been used since ancient times for seals, intaglios, and jewelry, with significant cultural and historical importance in many civilizations. The label 'Jade Calcedoine' is misleading; chalcedony is not jade. This misnomer is sometimes used in the trade to describe dyed chalcedony resembling jade, as a marketing tactic.

In the field, natural chalcedony typically forms in nodules or as cavity fillings. Its waxy luster and conchoidal fracture are key identifiers. For the specific item in the image, identification involves observing the color (intense, uniform red often points to dyeing, especially if there's no visible banding), hardness test (scratches glass), and translucent quality. A hot point test can sometimes reveal dye by discoloration or an odor, though this is destructive. The beads are faceted, which is a common cut for gemstones used in jewelry. Locations producing natural chalcedony include Turkey, Brazil, India, and various parts of the USA. When purchasing, be aware of common dye treatments, especially for vibrant, uniform colors like the red shown.