Zhuni vs. Hongni – The Red Ores of Yixing
So you want to get into Yixing teapots, but want to know what exactly you’re getting—not to mention buying—into? Yixing teaware is a world of myth and rumour, reputation and artistry, as much hype as the art world, and many times the forgery. But behind all of that, there must be objective, hard truth, right? After all, the items in question are literally made of stone.
Perhaps the most confusing categorisation is the distinction between the hongni and zhuni ores: what is their relationship, what are their differences, and do they both even exist anymore? By the end of this article, we hope to clear up confusion between the two terms as we define them, and give you five ways, using five different senses, to tell genuine zhuni from hongni, should you be in the market for a new (or antique) Yixing teapot.
Hongni and zhuni are simply two different kinds of ores, with different mineral compositions. While hongni is an argillaceous siltstone, a sedimentary rock formed with silt-sized particles, zhuni is a mudstone which has often concreted within other sedimentary rocks, with mud-sized particles (finer than silt). In fact, the raw ores look quite different, though both become reddish when fired.
Different raw Yixing ores, from left to right: lüni, duanni, zini, hongni.
‘Hongni’ means literally ‘red clay’ or ‘red mud’ and ‘zhuni', ‘vermillion clay’ or ‘vermillion mud’, reflecting their final colours (but more on this below). Hongni is a broader term, referring to quite a range of different ores, not all of which are even suitable for making teaware; in contrast, ‘zhuni’ refers to a specific ore of this finer composition found in Yixing. Zhuni is also rarer, and its rarity and fineness make it usually the more valuable material; they also make it a target for forgery, with teapot makers or sellers sometimes representing inferior material or hongni as ‘zhuni’, which is also very unfair to the hongni, which has valuable qualities of its own.
So, confronted perhaps with a nice-looking (or attractively-priced) teapot labeled ‘zhuni’ or ‘hongni’ in an unfamiliar teashop somewhere, or perhaps with a reddish Yixing-esque teapot with no clear label at all, how does one recognise one from the other, the genuine from the counterfeit? While the simplest and only airtight way would be to have observed the material from mining in Yixing (perhaps in the ‘70s) all the way through its shaping and firing, this is also the most impossible. Confronted by that teapot, the best thing to do is get what information you can from the dealer and perform whatever of the following tests you can, using sight, scent, sound, touch, and taste:
Colour & Lustre
First of all, the obvious: to the untrained eye (and by the end of this article, that may no longer include you, dear reader), teapots made with the two Yixing ores may look virtually identical. Indeed, sometimes zhuni is even classified as a subcategory of hongni because of this superficial similarity, though it is just as often separated because of sufficiently different characteristics. It is frequently said that zhuni should be darker than hongni, with a more intense orange colour, and that it should be distinctly shinier as well. These are indeed qualities generally associated with the two types, and are something to look out for, but are probably not the best indicators. This is because the blending of ores can result in a wider range of initial colours, especially in hongni, and moreover the temperature at which the ores are fired has a more dramatic effect on the final colour.
Two Cannon Spout Yixing teapots of hongni (left) & zhuni (right), showing the subtle difference in colour.
Likewise, it is the particle size that ultimately determines the lustre of the teapot’s surface: smaller particles result in a greater shininess. While it is true that zhuni should have a smaller particle size, for reasons addressed below, this has as much to do with the processing of the ore as its composition, and the difference may be subtle. In addition, less-than-scrupulous ceramicists may alter the colour of the material to fetch a higher price, further weakening the reliability of appearance alone, and which brings us to our next diagnostic. Nevertheless, a different characteristic appearance is the first difference between these two.
This one is simple: there should be no chemical smell in a quality Yixing teapot. Being made of stone, it should smell at most, well, stoney. Any other scent may indicate a chemical colourant added to create a bright colour not found in nature, or to pass off an inferior or less-prized ore for one worth more. Give the teapot a sniff! Water and heat might bring out its aromas more strongly.
Size & Texture
While all Yixing ores shrink upon firing, the different composition of hongni and zhuni ores results in a significant difference in shrinkage: on average, hongni shrinks around 15% of its unfired size, whereas zhuni shrinks between 20 and 25%! This can result in an easily observable difference in size for two pots that were shaped or moulded identically. In addition to a fine particle size, this means that fired zhuni will be noticeably denser as well, heavier for its size and with a smoother, more stone-like surface texture. Run your fingers over the surface of the teapot: in contrast to zhuni’s smoothness, a hongni teapot may feel sandier. Of course, this surface texture depends a lot on the exact composition and grinding of the ore, and a smoother hongni is even a sign of higher ore quality. Perhaps most importantly, however, it means that larger zhuni pots will likely crack in the kiln, so it is very rare to find one that will hold more than 150 millilitres; an enormous 'zhuni' teapot is therefore less likely to be genuine.
Perhaps the most fun to test out—just be careful when trying it out in a teashop! Neither you nor the owner will appreciate broken pottery, especially if it turns out to be genuine. To perform the test, take the teapot’s lid, and tap or rub it gently on the body: the higher density of zhuni means it will have a higher pitch than a hongni teapot of the same size and shape. Once you know what kind of sound to listen for (have a look at our video for a good example), you can use this test generally to test the density of any clay teapot. Of course, do be delicate, though quality Yixing ore is fairly durable for its size and thickness.
While not a test one can usually do before purchasing a teapot, if you have the opportunity to do so, the different qualities of each ore will make themselves known—and here we also get to the different uses of each kind of teaware. While we may have implied up to this point that hongni is of inferior quality to zhuni, this isn’t to say that a material of a lower density can’t benefit brewing—indeed, this is where the famed ability of Yixing comes into play. Generally, a lower-density, more porous material will interact with the tea more, smoothing down its astringency, while adding back the flavours from previous brews (and a little clay flavour as well, of course). Thus hongni teapots are well-suited to teas which can benefit from the mollification of excess bitterness, roasting, and/or astringency, like (especially young) Sheng Pu’er or heavily-roasted Wuyi Yan Cha. On the other hand, teas which should retain all of their aromatic qualities, like Taiwanese or Dancong oolongs, are better served by the stone-like density of a good zhuni. In fact, the compact shape and tight-fitting lid will provide superior heat retention to that of a gaiwan, extracting even more flavour for those teas which do best with hotter water.
This gives you some indication of how best to use the different types (at least, in our humble opinion), but can also be used as a test for the different types: hongni should alter the flavour more, smoothening down the flavour compared to zhuni or a glazed brewing vessel, whereas zhuni should provide a more aromatic flavour in comparison. These are rather subjective measures, but, in a sense, provide the only real and only important test for you, the tea drinker: which teas taste better in which teapots? This is, after all, what we as tea lovers and connoisseurs are seeking: the best tea drinking experience.
Written by Dimitri