Sea Glass Blog — manganese dioxide
Where does purple sea glass come from?
Posted by Kirsti Scott on
While some purple sea glass started out as intentionally purple pieces, many pieces of purple or amethyst sea glass were originally clear glass. They changed color over time in a process called solarization, due to the chemical composition of the glass. All glass is made of silica, but sometimes there are impurities in the sand, such as iron, that can cause a light green discoloration. To offset the discoloration, glassmakers add different ingredients to the molten glass. One of these decolorizers is manganese dioxide, sometimes called “glassmakers’ soap.” Manganese dioxide has been used for thousands of years for this purpose,...