Carnelian

Hardness: 6.5-7 on the Mohs scale. Color: Translucent reddish-orange to brownish-red, sometimes with banding. Luster: Vitreous to waxy. Crystal Structure: Trigonal (as a variety of quartz), cryptocrystalline structure. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Carnelian is a form of chalcedony, which typically forms in cavities in volcanic rocks. It forms from silica-rich waters depositing microcrystalline quartz over long periods. The distinctive red-orange color is due to the presence of iron oxides (hematite) within the silicon dioxide structure. It is typically found in younger geological formations, often in alluvial deposits.

Carnelian has been used for thousands of years in jewelry, carvings, and ornamental objects. Its attractive color and relative durability make it popular for beads, cabochons, and personal adornment. Historically, it was used for seals and intaglios. Today it's primarily used in jewelry and decorative art.

Carnelian was revered by ancient civilizations, including the Egyptians, Greeks, and Romans, who used it in protective amulets and signet rings. Ancient Egyptians called carnelian 'the setting sun' and considered it a symbol of life. It is also believed by some to have properties that stimulate creativity, courage, and vitality.

To identify carnelian in the field, look for its distinctive reddish-orange to brownish-red translucent color and waxy luster. It feels cool to the touch. It will scratch glass but cannot be easily scratched by a knife or steel nail due to its hardness. Common locations include India (especially the city of Pune), Brazil, Uruguay, Madagascar, and parts of the United States. Tips for collectors include looking for tumbled pieces in riverbeds or in areas with volcanic activity where silica-rich solutions would have formed. Beware of heat-treated or dyed agate that can mimic carnelian.