The Clays of Yixing

There is no single “zisha.” The word — 紫砂, “purple sand” — is an umbrella for a whole family of ores dug from the hills around Yixing, each firing to a different colour and, more importantly, brewing tea in a different way. Most are named for the colour they turn after the kiln, not the colour of the raw rock. Learn five of them and you can read almost any pot.

The deciding factor is mostly iron and density. More iron oxide makes a clay redder and denser; a denser wall has smaller pores, holds heat differently, and either traps a tea's aroma or drinks it in. That single property — porosity — is why a fragrant oolong and an earthy ripe pu'er want completely different pots.

Zini 紫泥 · purple clay

The backbone of Yixing, and the clay most people picture: a deep purple-brown with roughly 7–8% iron. Medium-grained and moderately porous, it rounds and softens a tea without erasing it — forgiving, versatile, and the easiest place to start. The prized sub-ore 底槽清 (di cao qing) comes from the bottom layer of the seam and fires to a richer, more complex tone. Best friends: ripe pu'er, aged and roasted oolong, black tea, dark teas of all kinds.

Duanni 段泥 · buff / tan

The pale one — sand-beige to warm yellow — and the lowest in iron (around 2%). Duanni is the most porous and the best at holding heat, so it mellows and smooths a brew more than any other clay, rounding off harsh or storage notes. Wonderful for ripe pu'er, white tea and aged teas. One caveat: its light surface stains easily, so it rewards careful, consistent brewing.

Zhuni & Hongni 朱泥 / 紅泥 · vermilion & red

The high-iron reds (zhuni runs near 10%). Zhuni is dense, fine-grained and dramatic: it shrinks so much in the kiln that the surface often crinkles (the famous 皺 “wrinkle”), and a finished pot rings bright, almost metallic. Because its tiny pores absorb little, it concentrates and lifts aroma rather than muting it — the right pot for fragrant teas: Taiwan high-mountain oolong, Phoenix dancong, fine black tea, heavily roasted oolong. Hongni is the broader red family; the celebrated 大紅袍 belongs here.

Benshan Lvni 本山綠泥 · green clay

The exception that's named for its raw colour — a pale green ore that fires to a soft beige-buff. Scarce, low in iron, fine and delicate; gentle and porous, it suits lighter, more aromatic teas and is often blended into other clays rather than used alone.

Jiangponi 降坡泥 · a famous blend-in-the-ground

Not a colour but a place: an ore turned up when a hillside road was cut, naturally mixed between red and duan, firing to a warm reddish-tan with visible grit. Mellow and characterful — lovely for black tea and roasted oolong.

Which clay for which tea

Clay	Character	Brews best
朱泥 Zhuni	Dense, lifts aroma	High-mountain oolong, dancong, black tea, roasted oolong
紫泥 Zini	Versatile, rounds	Ripe pu'er, aged & roasted oolong, black tea
段泥 Duanni	Porous, mellowing	Ripe pu'er, white tea, aged tea
本山綠泥 Lvni	Delicate, gentle	Lighter, aromatic teas
降坡泥 Jiangponi	Warm, characterful	Black tea, roasted oolong

Raw ore, not chemistry

One word matters more than any colour: 原礦 (yuan kuang), raw ore. True zisha gets its colour from minerals in the clay itself, brought out by fire. Cheap pots are often dyed with metal oxides to fake a rare tone — a “clay” that looks suspiciously uniform, garish, or oddly bright. Real ore looks alive: slightly uneven, sandy underfoot, deepening to a soft 包漿 patina with years of use. If a colour seems too perfect, it usually is.

That is the whole reason we work straight from named potters in Yixing: so the clay in your hand is the clay it claims to be.

Sources, for the curious: Teasenz, Mud & Leaves, TeaForum.org. Iron figures are approximate and vary by seam.