Dolomite

Dolomite is a calcium-magnesium carbonate mineral (CaMg(CO3)2), named after the French geologist Deodat de Dolomieu, who first described it in 1791. It supplies both CaO and MgO to glazes in equal molar amounts.

Magnesium is what makes dolomite special. MgO is a slow, strong flux at high temperatures that produces characteristic “dolomite matte” surfaces: soft, buttery, satin finishes with a slight silky texture that feels pleasant in the hand. These glazes are highly prized for functional pottery, tea bowls, and tableware.

Magnesium also affects color development. Cobalt in a magnesium-rich glaze shifts from bright blue toward pink-purple. Iron becomes more muted and earthy. Copper tends toward dusty blue-green rather than bright turquoise.

Dolomite’s dual-flux nature means you can use it to replace both whiting and talc in a recipe, simplifying your glaze palette.

Typical usage: 5 to 20 percent in cone 9 to 10 matte and satin glazes. A classic “dolomite matte” recipe uses dolomite as the primary flux with feldspar and kaolin, producing a food-safe satin finish.