A polished agate egg from Brazil, cut and finished to reveal an open geode of sparkling quartz at its centre, set against the stone's natural banding. Agate forms layer by layer as silica-rich fluids fill cavities in volcanic rock; the quartz pocket at the core is the final stage of that slow filling.
Mineral: Agate (chalcedony, a variety of quartz, SiO₂) Crystal system: Trigonal Origin: Brazil Hardness: 7 on the Mohs scale; durable and easy to handle Treatment: None Dimensions: 6 × 6 × 9.2 cm Weight: 420 g Note: Acrylic stand included
