If you've read our guide to Type A, B, and C jadeite, you already know that treatment status is the single most important thing to verify before buying. What we haven't covered yet is who actually does that verifying — the laboratories, standards, and certificates that turn "I think this is real" into "this is documented." Since the vast majority of the world's jadeite passes through Chinese hands at some point — mined in Myanmar, but cut, traded, and overwhelmingly authenticated in China — understanding China's testing system is genuinely useful, even for a buyer who's never set foot there. It's also, quite literally, how every piece in our own collection gets its paperwork — so this is a look at the real labs behind our own certificates, not just the famous name everyone's heard of.
Why authentication needs a lab, not just an eye
A trained gemmologist can spot many treated stones on sight — unnatural uniformity, a slightly plastic sheen, dye pooling in surface cracks. But a well-executed Type B (bleached and polymer-impregnated) or Type C (dyed) treatment can fool even experienced eyes, and reliably telling it apart from untreated Type A material takes lab equipment: infrared spectroscopy for polymer resin, Raman or UV-Vis spectroscopy for dye. That's the entire reason a testing lab exists — to answer, with instruments rather than opinion, a question that can carry a ten-times difference in value.
The national standards behind every certificate
China's jadeite testing system is built on a small set of national standards (guóbiāo, GB), published by China's national standardization body:
GB/T 16552 sets out gemstone nomenclature — the standardized names labs must use, which is why a certificate says "jadeite" (翡翠) rather than a vaguer term.
GB/T 16553 defines gemstone testing methods generally — the instrumentation and procedures a lab must follow to reach a conclusion.
GB/T 23885-2009, "Jadeite Grading," is the standard specific to jadeite, and it's the origin of the Type A/B/C treatment classification that's now used across the entire jadeite trade, not just in China. Any lab operating in China is expected to test and report against these standards, which is part of why the classification system is so consistent from one certificate to the next.
The labs that actually do the testing
NGTC (National Gemstone Testing Center) is the dominant name in Chinese gem certification. Founded in Beijing in 1992 under China's Ministry of Natural Resources, it's a state-affiliated laboratory with branches across major Chinese cities, and it's the institution most closely associated with popularizing the A/B/C system in the first place. For a jadeite buyer, an NGTC certificate carries the most immediate trust and the fastest, most widely recognized verification — reports are typically returned in days.
NGTC is the name most buyers have heard of, but it isn't the only accredited option, and it isn't the whole story of where jadeite actually gets tested. A huge share of the world's jadeite — mined in Myanmar — is cut, traded, and certified in one small cluster of Chinese cities in Guangdong province, above all Sihui, along with nearby Guangzhou and Shenzhen. Sihui alone employs more than 200,000 people in the jadeite trade and does over 100 billion yuan in annual sales — it's less well known outside the trade than Beijing's NGTC, but it's arguably the beating heart of the entire jadeite industry, which is exactly why so many accredited testing labs are clustered there rather than in Beijing.
That's also where our own certificates come from. Here are the labs that have tested pieces in our collection:
Zhongzheng Jewelry Appraisal Center (中正珠宝鉴定中心), with locations in Sihui and Guangzhou, is one of the labs we use most. Its certificates carry the CMA mark alongside its own "ZZAC" accreditation logo, and — like most labs in this cluster — test against GB/T 16552 and GB/T 16553.
Zhongjian Jewelry and Jade Appraisal (Guangdong) Co., Ltd. (中监珠宝鉴定), based in Zhaoqing (the wider municipal area that includes Sihui), issues certificates carrying CMA and CCAL accreditation marks in addition to the standard GB references.
Beijing Huashou Guojian Jewelry Testing Group, Sihui Branch — trading as "HSNGTC," a name that deliberately echoes NGTC's — is a private testing group headquartered in Beijing with a dedicated branch in Sihui, carrying its own CMA registration and a "GII" art-and-jewellery mutual-recognition mark.
HZDK Lab (华质地硷珠宝玉石检测中心) operates out of Shenzhen's China Jewelry City, one of the country's major jewellery wholesale complexes, and is nationally accredited (CMA) for precious metal and jadeite identification.
China Inspection Commercial Union (Guangdong) Quality Inspection Co., Ltd., Sihui Branch ("ZJSL") rounds out the group — another Sihui-based, nationally accredited lab specialising in gem and jewellery identification.
None of these names carry NGTC's brand recognition outside the trade, but each is a properly accredited testing body operating in the same regulatory system, working to the same national standards, in the same city where most of the world's jadeite actually changes hands. Pieces that also include a gold or silver setting sometimes carry certificates that cite additional standards for the metal — GB 11887 (precious metal fineness) and GB/T 18043 (a testing method for precious metal content) — alongside the jadeite grading reference, since the certificate is verifying both materials at once.
Reading the marks that make a certificate trustworthy
Whichever lab issued it, a legitimate Chinese jadeite certificate carries a small set of accreditation marks: CMA (China Metrology Accreditation) is the one constant across every lab listed above, often alongside CNAS (China National Accreditation Service for Conformity Assessment) and the lab's own logo, like the ones above. A certificate lacking any recognisable mark, lab name, or contact information is a signal to look more closely.
The fields that matter most are the identification result — it should say 翡翠 (jadeite) specifically, not a vaguer term for "jade" that could cover other minerals — and the remarks section, which should plainly state 翡翠（A货）, "jadeite (Type A)," for untreated material. Weight, shape, and a photo of the actual piece should also be present, so you can compare the certificate to the item in hand.
Verifying a certificate yourself
Every reputable lab issues certificates with a certificate number and QR code linking back to its own database. Scanning it, or entering the number on the lab's website, should return a record matching the stone's weight, shape, colour, and photo — catching the two most common problems: a certificate that was never real, or a real one passed off with a different, usually lesser, stone.
NGTC versus Western labs like GIA
GIA, the lab most Western buyers associate with diamond and gemstone grading, also assesses jade, but for a different purpose. NGTC and China's domestic labs are built around answering the question the jadeite trade actually cares about — natural or treated, and which type — quickly. GIA reports serve Western insurance, appraisal, and estate documentation better, and typically take much longer to issue. Neither replaces the other; a piece meant for long-term keeping or eventual resale in Western markets can reasonably carry both.
What this means for you as a buyer
You don't need to become an expert in Chinese accreditation systems to buy with confidence — you need to know that the system exists, that it's rigorous, and that a properly issued certificate, whether from NGTC or from one of the accredited Sihui-cluster labs above, is a real answer to a real question, not a formality. Every piece we sell is certified Type A, untreated, natural Burmese jadeite, tested by one of the labs listed here, so you're never relying on guesswork, ours or yours. If you'd like to see how to read your own piece's certificate, or have questions about which lab tested it, we're always happy to walk through it with you.