Hokkaido Kaminokuni Black Silica Approximately 1.4kg This item is offered at a bargain price due to oxidation, which has caused rust. The Black Silica on offer was sourced from the Kaminokuni-cho, Kamimei district, Tenkawa River headwaters in Hokkaido. It is a rare stone, as its extraction has ceased. This is the same type of Black Silica used in bracelets and bath sets, but this one is oxidized. Rust removal is required before use in the bath, and it cannot be used in water. #BlackSilica