Color: Imperial Dimensions: 7.90 x 5.70 x 4.00 mm Weight: 2.75 carats Origin: Brazil Shape: Oval Cut: Mixed Clarity: Treatment: None Certificate: Stone Count: 2
Provenance
Level 2 - On-site Contact
We purchased this gemstone from a contact with direct access to the mine location and with whom we have maintained a long and trusted business relationship. Our supplier has clearly reported on the exact mining locations and production practices applied. On several occasions we have visited the mining operations ourselves and have witnessed the extraction process. We therefore have very good visibility of the gem's life cycle and can testify fairly confidently to the provenance of this gemstone.
Country of Origin: Brazil
Mining Location: Boa Vista, Minas Gerais State
Imperial topaz was found in Ouro Preto in 1751. Initially called "Brazilian ruby," it was correctly identified as topaz in 1763.
Most imperial topaz mines are located in the hills west of Ouro Preto, nearby the villages of Rodrigo Silva and Dom Bosco. This particular stone was extracted at the Boa Vista mine.
Imperial topaz mining in Ouro Preto is done using the open pit technique as the ground has been intensely weathered by erosion and makes for easier extraction. It consists of a talc-clay rock called "brown terrain" of varying thickness and cut by thin kaolinite veins. Imperial topaz is found within the kaolinite veins alongside quartz and hematite.
The sterile overburden ground is removed with excavators and loaded on trucks. When the miners reach a kaolinite vein, they extract it carefully in order not to damage potential imperial topaz crystals present. After washing, the concentrated ore is ready for sorting on a slowly moving conveyor belt and the imperial topazes are handpicked out.
The water used for the washing plant is left to rest and once the clay settles out, the clean water is released harmlessly into the environment. No chemicals are used in the process. Once the area is mined out, the miners have a legal obligation, by Brazilian law, to replant the mine site and the tailings with local vegetation. This allows nature to reclaim the area.
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