Polished chrysoprase (likely)

A polished, blue-green to gray-green, waxy/lustrous cryptocrystalline quartz with dark brown-black dendritic or matrix-like inclusions; Mohs hardness 6.5–7, no visible cleavage, conchoidal fracture, and specific gravity about 2.6. The blue-green coloration may also indicate chrysocolla-bearing chalcedony or turquoise matrix, so exact identification requires testing.

Forms when silica-rich fluids fill cavities and fractures, with nickel or copper minerals producing green-blue color; commonly associated with volcanic rocks and weathered ultramafic zones, generally formed during relatively recent hydrothermal or weathering episodes.

Used for cabochons, beads, carvings, and ornamental polished stones; lower-grade material is primarily decorative or collectible.

Chrysoprase is the best-known green chalcedony variety, while blue-green material is often sold under trade names such as “chrysocolla chalcedony.” Color can fade with prolonged heat or sunlight.

Common sources include Australia, Brazil, Poland, Tanzania, and the United States. A glassy waxy luster, hardness near quartz, and lack of cleavage help distinguish it from softer turquoise or dyed stone; laboratory Raman/XRF testing is recommended.