Opal RGB 4mm round coin

Compatible with COE 33 / borosilicate glass

These coin opals are flat & polished on both sides and rounded & polished along the edges. The stones are 1mm thick. Each stone has a black base and red, green, blue and yellow fire. The fire in each stone varies quite a bit depending on the amount of light. More green with less light and more red and blue in higher light environments.