Gerstley Borate

Gerstley Borate

Gerstley Borate is a naturally occurring boron-rich mineral used as a flux in ceramic glazes, particularly in low and mid-fire applications. It helps lower the melting temperature, promoting smooth glaze flow and enhancing surface gloss. Due to its high boron content, it also improves glaze adhesion and contributes to the development of rich, variegated textures. Gerstley Borate is known for its ability to create stable, semi-matte to glossy finishes, but its natural variability and solubility can sometimes cause glaze inconsistencies. As a result, many potters and manufacturers substitute it with more consistent boron frits for greater reliability in glaze formulations.