Black Liquid Underglaze is a deep obsidian black that is dark and smooth at cone 05, fluxes into a soft glaze-like surface at cone 6, and maintains a deep black tone with a soft sheen all the way to cone 10. Though the underglaze does become glaze-like, a clear gloss glaze can give Black an impeccably smooth finish with relatively good color, thought it can cause small moments of transparency in the surface.