ZINC OXIDE

Only available source of zinc for glazes.

A secondary flux, but above 10% tends to produce frost-like matt surface, a degree of opacity and occasional pinholing.
Also makes glazes more susceptible to crawling.

Formula: ZnO

Zinc oxide is a fluxing agent with a medium to high melting point, but only when mixed with other fluxes.

In small quantities, it improves the brightness.

In larger amounts, it can lead to opacification or dulling of the glaze.

Main ceramic use:

Enamel opacifier (used in small quantities)

Mattifying agent for stoneware glazes

For the realization, in high concentration, of crystallizations.

ZINC OXIDE

This is the only source of zinc available for ceramics.

In small proportions, it acts as a flux; introducing 10% into a glaze causes clearly matte surfaces with a high degree of opacity and under certain conditions crystallization effects.

Gives "elasticity" to glazes.