20.76 ct. Natural Ethiopian Black Opal.
Dimensions: 21.72x16.50x9.90 mm.
Black Opal have been mined in Wollo District in Ethiopia since 2013. The Opal mine is situated around 100 Kms. from the historic town of Lalibela and around 410 Kms. from Bahir Dar. Mines in Wollo District have produced White precious Opals, Dark grey Opals, Fire Opals and Black Opals. Black Opals are found between the volcanic rock and clay rich soil.
This Black Opal is multicolored. It has red as the primary play of color on one side and blue as the primary play of color on the other side. It was tested whether it was hydrophane and was found it did not absorb water like the white and crystal Opals. The weight before soaking in water was 20.7647 ct., and after soaking for 5 days, its weight was 20.8125 ct. The difference in weight is negligible.
This Black Opal is a polished freeform and the white silica in some places have not been removed to show that it has not been treated in anyway.
This freeform shape can be used as such or can be recut to the desired shape.