When it comes to Da Shui Tan Green Clay, it originates from the Da Shui Tan area in Lishu, yet it is not mined inside the pond itself. Towards the end of the Republic of China era, continuous open-pit excavation of the shallow surface ore veins struck underground water. As digging went deeper and deeper, the pit was eventually flooded and has remained untouched and unmined ever since.
For this reason, mining inside the pond is impossible. The actual excavation site is a tunnel dug into the roadside ground right beside the pond. Zisha ore veins never exist as isolated single points; they spread horizontally across an entire plane. It is very likely that the ore extracted from this roadside tunnel belongs to the same vein system as the one beneath Da Shui Tan.
Ancient miners targeted Da Shui Tan primarily for pottery clay used to make large water vats, starting back in the late Ming Dynasty. They did not dig this massive pit specifically for Zisha clay. It was during vat clay mining that pockets of Zisha were accidentally discovered deep within the pottery clay layers. As excavation proceeded, the pit gradually shrank in scale. Therefore, identical ore seams run horizontally on both sides of the original pit. This material is known to collectors as either Da Shui Tan Green Clay or Da Shui Tian Qing Clay, and the two occur in overlapping upper and lower strata.
We first sourced this ore through exclusive private channels around 2017 or 2018. This deposit only became available in the 2010s, as the flooded pond bed was never accessible for mining. Miners in the Huanglong Mountain range rarely explored the southern Lishu area adjacent to Da Shui Tan for decades. It was not until the 2010s that a new tunnel uncovered the Tian Qing and Green Clay from the Da Shui Tan vein, which we then purchased and processed ourselves.
When we first acquired the raw ore, miners did not classify the material as green clay - Lüni at all, because genuine lüni was extremely scarce and unfamiliar to them. Even veteran miners with decades of experience had never encountered it and could not identify the material. The purplish ore was simply called purple clay - Zini instead of Tian Qing, while the green-hued material was mistaken for Duanni due to the lack of professional identification. Hardly anyone valued this special clay at the time.
We stockpiled large quantities long before this material gained popularity, having recognized its outstanding quality during preliminary refining trials. After purification, the finished clay delivered exceptional performance. We were one of the first to develop and popularize this specific lüni, which quickly won widespread acclaim across the market, We kept its origin and rarity confidential at first to prevent mass hoarding and sudden price surges until we got even more of this ore, once our finished teapots were released, detailed introductions became unavoidable, and the clay soon became highly sought-after.
Lüni is extraordinarily rare across Huanglong Mountain’s ore reserves. Roughly speaking, purple clay accounts for around 90% of all mineable Zisha ore, while lüni makes up less than 0.1%. Although lüni veins are scattered across wide geographical areas, they are notoriously hard to mine. Its ore seams are extremely thin and prone to mineral intergrowth with the strata above and below, much like a narrow territory easily encroached upon by neighbouring lands. Most material labelled green clay on the market is actually altered Duanni, its chemical composition transformed by long-term intergrowth.
What makes Da Shui Tan Green Clay unique is its ore seam thickness, reaching 10 centimetres or even over 15 centimetres. Its top layer consists of slate rock and the bottom layer is Zini, meaning intergrowth only occurs on the lower side. The slate above cannot merge with the lüni vein, leaving the upper portion fully protected, and a large volume of pure, unaltered Lüni preserved in the middle stratum.
All ore deposits feature stacked upper and lower layers, and contact points between different strata inevitably create intergrowth zones. While slate does not chemically blend with lüni, the boundary between the two is uneven and undulating. The transition layer between lüni and the underlying Zini can also be quite thick, resulting in raw chunks mixed with both purple and green particles. Underground miners cannot meticulously separate each stratum along precise borders, so raw material is always excavated as a blended mass. Processing requires careful picking to remove slate fragments from the top layer, impure Zini from the bottom, and tiny black mineral spots scattered throughout.
All Huanglong Mountain clays require sorting, yet lighter-coloured varieties demand far stricter selection. Darker clays can naturally conceal minor impurities, black specks or trace intergrowth, as their deep hue provides ample coverage. Lüni, however, is pale in tone; every intergrown mineral is darker by comparison, and small blemishes stand out starkly. In short, the lighter the clay colour, the higher the sorting difficulty.
Counterfeiting Zisha clay follows a fixed rule: simpler materials can be blended to imitate complex varieties, but complex clays cannot be reduced to replicate simple ones—only additive mixing is possible. For this reason, perfect counterfeits of lüni are nearly impossible to produce. The most common substitute on today’s market is white Duanni, chosen for its similar pale tone or even lighter shade. White Duanni has a critical flaw: its jade-like gloss only appears after high-temperature vitrification, meaning the lustre is artificial rather than inherent. Genuine lüni carries a subtle natural jade texture straight out of the kiln, which deepens and refines gradually through long-term brewing and use. White Duanni will never develop this authentic aged patina no matter how much it is used. If you buy a brand-new teapot with an overly strong, shiny jade finish, it is almost certainly counterfeit; genuine lüni teapots are always subdued at first and develop their glow over time.
Green clay - Lüni is softer and more tender than purple clay - Zini, requiring shorter ageing periods. Many Zhuni (vermilion clay) varieties need no ageing at all, Zini typically requires two years of resting, while lüni matures fully in just one year. Vacuum pugging eliminates the need for ageing entirely, but we rely on manual clay refining for lüni. Vacuum processing causes severe damage to the delicate molecular structure of tender ore, so hand refining is always preferred for this material. Our standard workflow includes six months of water-soaked weathering followed by just under six months of resting. We submerge the ore in water for weathering rather than leaving it exposed outdoors to avoid excessive material loss, given its extremely high value.
Genuine Da Shui Tan Green Clay is barely available on the open market today. Most stock consists of fakes, and authentic pieces command exorbitant prices. Owners are unwilling to sell in bulk, only releasing tiny batches of a few dozen jin at a time. We also refrain from mass production or low-cost sales, as this finite ore will eventually run out entirely, and its value will appreciate the longer it is stored. This is why we rarely sell raw clay or unprocessed ore.
Crafting finished teapots from this precious clay yields the highest profit margin and serves as tangible proof of our material sourcing strength for customers. Selling loose clay brings far lower returns, and raw ore generates the least profit of all. There is little financial incentive to part with our prized ore reserves, which is our core reasoning for keeping most stock for in-house teapot production.
Watch the full video of Part 1
We have to sort through everything carefully here. This is Zini; tiny particles of Zini can be found scattered throughout the raw material. Just because there’s none visible on the surface of a large chunk doesn’t mean there isn’t any inside. That’s why we have to break everything into small pieces for inspection, picking through every tiny grain one by one.
These bits are impurities. Even so, it’s impossible to extract 100% pure Zini There’s also a large amount of lüni mixed in, and complete separation cannot be achieved. A lot of green clay ends up getting discarded as well, leading to substantial material loss.
We also need to pick out all the rust stains inside. These yellow patches are rust stains, and every single one has to be removed. In the end, only around 50% of the raw ore can be retained after sorting.
The ore itself is already very expensive, and losing half of it to sorting waste drives costs up drastically. This explains the huge price gap between finely sorted clay and unsorted stock, not to mention the staggering labour costs.
Speaking of labour, a worker can only sort 1.5 to 2 kilos of material in an eight-hour shift from morning till night. Just 1.5 to 2 kilos. That’s why labour expenses are so considerable.