gems, corundum, Tanzania.12, Umba, East Africa, ruby, sapphire, fancy sapphire

During the late 1980s, the first author Terrence Coldham (TC) purchased a tin trunk filled with rocks and rough gem materials from Orestis Palos, at the time the owner of a Sydney-based gemstone wholesaler trading as Gempalos Co. Although Orestis rarely spoke about his life before arriving in Australia, he did mention spending time in Tanzania, and that was the origin of the materials in the trunk. Given author TC’s long-standing interest in corundum, the contents were immediately fascinating: coarse-grained rocks containing corundum crystals, along with many loose pieces of rough sapphire in a wide range of pastel colours. Orestis explained that all the material was from Tanzania, and aside from the ruby in zoisite, everything had come from the Umba region. Soon after acquiring the rough material, several stones were selected to be cut and polished by well-respected Sydney lapidary Tony Maynard, resulting in a collection of faceted and cabochon Umba sapphires which are still in author TC’s possession. Despite having visited Tanzania several times over the years, TC had never managed to reach the Umba gem fields, the very source of the Umba sapphire collection. That changed in October 2024 when two of the authors (TC and SS) travelled to Tanzania, specifically arranging a visit to Umba.