Feldspar: The Universal Flux

If kaolin is the body of porcelain, feldspar is the quiet hero of its surface. It appears in nearly every glaze ever made, yet almost no collector has heard of it. This is its story.

What It Does

Feldspar is a family of aluminum-silicate minerals, rich in potassium or sodium. Its superpower: it melts at a lower temperature than the clay itself. Added to a glaze recipe, feldspar acts as a flux — pulling the melting point down so that silica and other refractory materials can fuse into glass at achievable kiln temperatures. Without feldspar, most glazes would simply never melt.

The Subtle Variety

Not all feldspar is the same. Potassium feldspar produces a slightly stiffer, more resistant glaze; sodium feldspar melts more fluidly and produces glossier surfaces. The choice between them — and the exact proportion — is part of every studio's secret recipe. This is one reason two 'similar' Jian Zhan cups from different studios can have such different character: the underlying feldspar balance differs.

For the Collector

You don't need to know feldspar to appreciate a great cup. But understanding that every glaze is a precise chemical balance — chosen by an artisan, not an engineer — deepens your appreciation of the craft. It's the difference between seeing a beautiful surface and understanding the intelligence that created it. Every piece in our collection carries this invisible science in its visible beauty.