Geode with Metal Base — Rolled

The Geode is a geological structure formed by spherical to ovoid cavities in igneous or sedimentary rocks, the interior of which is lined with crystals formed by the gradual precipitation of minerals from hydrothermal solutions that percolate the cavity over time. The original cavity is formed by gas bubbles trapped in basaltic lavas or by the dissolution of nodules in sedimentary rocks. The internal lining is predominantly composed of quartz (SiO₂) in its different varieties — amethyst, hyaline quartz or chalcedony — or calcite (CaCO₃), depending on the chemical composition of the percolating solutions and the temperature and pressure conditions during mineral precipitation. The exterior of the geode goes through a mechanical rolling process, a polishing technique that progressively rounds off the edges and corners of the host rock, resulting in a smoothed external profile that contrasts with the preserved internal crystalline structure. Hardness: 3 to 7 on the Mohs scale (variable depending on internal mineral). Density: 2.60 to 2.95 g/cm³. Crystalline system: variable depending on mineral composition. The product is sold with a metal base included, ready for display. The measurements and weight reported refer to the complete product (geode + base). Available variations, approximate data: Weight: 0.130 to 0.500 kg (approx.) Dimensions: 10x4x4 cm to 14x7x7 cm (approx.)