Dense zircon white frit leadless frit
A frit is a type of ceramic glass. It is a combination of materials that, when melted together, are rendered insoluble and resistant to acid attack. They are, therefore, a means of introducing certain materials into a glaze which would otherwise be toxic. Frits can be used alone as low temperature glazes, e.g. raku and majolica, but generally they form the basis of a glaze recipe.