Sphalerite Raw Slab/Slice - A really unique piece! 19cm x 12.5cm - 485gm What is commonly called "Sphalerite" is often a blend of Goethite in Quartz with Chalcedony and Manganese inclusions. There is a lot of discussion online about what the actual components are and they can differ from piece to piece. In specimens described as goethite in quartz with chalcedony and manganese inclusions, the main material is quartz or chalcedony (both forms of silicon dioxide, SiO₂) containing multiple included minerals. Goethite, an iron oxide mineral, contributes brown, golden, or black internal patterns and banding. Manganese-bearing minerals can add darker tones, including black, grey, or deep brown colours. Chalcedony, a microcrystalline form of quartz, often gives the stone a smooth, opaque to translucent base with a waxy to dull lustre. These materials are usually opaque or only slightly translucent, with complex internal layers, plumes, or patchy patterns. Hardness depends on the dominant material, but quartz and chalcedony are around 6.5 to 7 on the Mohs scale, making the stone reasonably durable.
