Duftite on Calcite | green crystal, rare mineral specimen from Tsumeb Mine, NamibiaDuftite on calcite from the legendary Tsumeb Mine in Namibia is a classic combination that highlights the rich secondary mineralization of this world famous locality. In such specimens, sharp, transparent to colorless rhombohedral calcite crystals form the dominant framework, often showing excellent geometry and sometimes interpenetrant habits, while the green to pistachio green duftite (PbCuAsOOH) occurs as coatings, selective patches, or