A fine dioptase with calcite and quartz specimen from the classic locality Guantala, Mindouli, Democratic Republic of the Congo. The piece displays vivid, emerald-green dioptase crystals beautifully contrasting with a sparkling matrix of quartz and calcite. The dioptase shows an intense, saturated color typical of high-quality Congolese material and stands out clearly against the transparent to slightly honey-colored quartz crystals. This natural tri-mineral association is well balanced and highly aesthetic, with strong visual appeal.