Technical answer: Agarwood (沉香 chénxiāng) is the resin-impregnated heartwood of Aquilaria trees, formed when the tree responds to wounding or fungal infection. It is the most precious material in the classical incense tradition, valued for a deep, sweet, resinous aroma — and so expensive that it is among the most heavily adulterated incense materials in the world.
Key facts: The name 沉香 means “sinking fragrance” — the finest resin-dense pieces sink in water. The top grade is called 奇楠 (qínán, cognate with Japanese “kyara”), which differs from ordinary agarwood in a specific, little-documented way.
Key Takeaways
- Agarwood = resin-impregnated Aquilaria wood (Thymelaeaceae), formed over years–decades in response to wounding or infection.
- The name 沉香 means “sinking fragrance” — resin-dense pieces sink in water.
- 奇楠 (qínán) is the top grade, distinguished from ordinary 沉香 by the “oil-wraps-wood” vs “wood-wraps-oil” distinction (explained below) — a point English content almost entirely misses.
- Agarwood is heavily adulterated; buyer-authentication knowledge is high-value.
- Traditional Chinese medicinal claims about agarwood are historical record, not modern clinical evidence.
What Is Agarwood?
Botanically, agarwood is the resin-saturated heartwood of trees in the genus Aquilaria (family Thymelaeaceae). Healthy Aquilaria wood is pale, light, and nearly scentless. The prized material forms only when the tree is stressed — wounded or infected — and produces a dark, fragrant resin that gradually saturates the wood over years or even decades.
Key species include Aquilaria sinensis (Chinese agarwood, 白木香) and Aquilaria malaccensis (the classic import, now heavily depleted). Because natural agarwood is so slow to form and so scarce, much modern supply is cultivated and induced by deliberate wounding.
Why It’s Called “Sinking Fragrance”
The name 沉香 (chénxiāng) literally means “sinking fragrance.” The logic is physical: the finest pieces are so dense with resin that they sink in water, while lower-grade, less-resinous wood floats.
This gives rise to the classic Chinese grading system (沉水 system), which is surprisingly poorly documented in English:
| Grade | Behavior in water | Quality |
|---|---|---|
| 沉水 (sinks) | Fully sinks | Highest resin content, most valuable |
| 半沉半浮 (half-sinks) | Partially submerged | Medium |
| 浮 (floats) | Floats | Lower (historically “黄熟香”) |
奇楠 vs. Ordinary Agarwood (the Distinction English Misses)
The single most useful thing to know about agarwood — and the point most English content omits — is the difference between ordinary 沉香 and the top grade, 奇楠 (qínán, Japanese “kyara”):
- Ordinary 沉香 is “wood wraps oil” (木包油). It is hard wood with resin veins running through it.
- 奇楠 is “oil wraps wood” (油包木). The wood fiber is so thoroughly transformed by resin that the material becomes soft and pliable. The traditional description is that it “shaves into curls and kneads into pellets” (削之成卷、捏之成丸) — and it is aromatic even at room temperature.
奇楠 is further graded by color into (traditionally) five grades: 白 (white), 绿 (green), 紫 (purple), 黄 (yellow), 黑 (black) 奇楠. Note: sources disagree on whether the purple/yellow grades are distinct grades or aging stages of the green grade — treat the color hierarchy as traditional, not settled science.
Etymology note: the origin of the name 奇楠 is genuinely uncertain. Theories include Sanskrit “Kāla” (black), Sanskrit “tagara” (a fragrant plant), and a “temple” reading. Some scholarship argues “tagara” is a mistranslation and that the Sanskrit word for agarwood is “agaru/aguru.” The honest position is “etymology uncertain; multiple theories.”
Adulteration: How to Spot Fakes
Because agarwood is so valuable, fakes are common. Common methods include:
- 煮油 (oil-boiling) — boiling ordinary wood in oil to add weight and scent.
- 高压灌油 (high-pressure oil injection) — forcing oil into non-resinous wood.
- 泡药水 (chemical/dye soaking) — dyeing and scenting non-resinous “white wood.”
- Substitution — using unrelated woods (Lauraceae, Burseraceae) with synthetic fragrance.
Practical authentication signals (traditional, not laboratory-grade):
- Burn behavior: genuine agarwood tends to produce white smoke with oil seepage when burned; many fakes produce black smoke.
- Aroma on gentle heat: real material gives a complex, sweet aroma when gently heated; fakes smell of “burnt wood” or perfume.
- The sink test: resin-dense material sinks (for ordinary 沉香 grading).
- No perfume note: synthetic fragrance has a one-dimensional “perfume” smell.
These are traditional buyer heuristics; laboratory or reputable-seller verification is the reliable route.
Traditional Medicine Claims: Historical Record, Not Treatment
Chinese sources (notably the 本草纲目) attribute to agarwood phrases like “行气止痛，温中降逆，补五脏” — move qi, relieve pain, warm the middle, tonify the organs. This is traditional materia-medica language, not modern clinical evidence.
LanDeng does not repeat these as therapeutic fact. They are recorded here as historical record / traditional belief, to preserve the cultural context without making medical claims.
Where Agarwood Comes From: Species and Geography
Agarwood is produced by trees in the genus Aquilaria (family Thymelaeaceae), native to South and Southeast Asia. The two names that matter most in the Chinese tradition are:
- Aquilaria sinensis (白木香, “white-wood fragrance”) — the Chinese agarwood, native to southern China (Guangdong, Guangxi, Hainan, Yunnan) and historically the source of domestic 沉香.
- Aquilaria malaccensis — the classic trade import from mainland and maritime Southeast Asia, now heavily depleted and listed under CITES.
Other Aquilaria species, and the related genus Gyrinops, also produce resin, and all are traded under overlapping names. The Flora of China entry for Aquilaria gives the botanical picture; trade names and species do not always map cleanly, which is part of why provenance matters.
How the Resin Forms: The Stress Story
Healthy Aquilaria wood is pale, light, and almost scentless. The resin that makes it agarwood is a defense response: when the tree is wounded — by a broken branch, insect boring, fungal infection, or deliberate cutting — it produces a dark, fragrant resin to seal and protect the wound, and over years to decades that resin saturates the surrounding wood.
Classical Chinese terminology distinguishes how the resin formed:
| Term | Meaning |
|---|---|
| 熟结 (shú jié) | Resin formed in a tree that has died and aged |
| 生结 (shēng jié) | Resin formed in a still-living tree |
| 虫漏 (chóng lòu) | Resin formed around insect boring |
| 脱落 (tuō luò) | Resin formed from an external wound or break |
Because natural agarwood forms slowly and unpredictably, most modern supply is cultivated — trees are deliberately wounded or inoculated to induce resin, then harvested after several years. “Natural” versus “cultivated” is therefore a meaningful distinction in the agarwood market, not a cosmetic label.
The Aroma: Three Stages on Heat
Agarwood’s reputation rests on how its scent unfolds as it warms, not on a single burst of smell. Classical appreciation names three stages:
- 头香 (tóu xiāng, “head/opening”) — the first impression as the material begins to release.
- 本香 (běn xiāng, “body”) — the main, sustained character.
- 尾香 (wěi xiāng, “tail/dry-down”) — the fading, deeper residue.
This staged release is why agarwood is traditionally heated (隔火焚香) rather than burned: a direct flame destroys the delicate top notes before you can smell them. High-grade 奇楠 is aromatic even at room temperature; ordinary agarwood needs gentle heat to open up.
Agarwood in Chinese History and Literature
沉香 is woven through Chinese written culture. The 本草纲目 records it as an aromatic material with traditional materia-medica associations (see below). In poetry and connoisseurship, agarwood appears as the benchmark of fragrance — the material that “sinks” because it is so dense with resin. The Ming compendium 香乘 devotes extensive entries to agarwood, its grades, and its substitutes. The chemistry of agarwood’s scent is well documented in the specialist literature (e.g., Naef’s review of agarwood volatiles); the grading and buying side lives in the grading guide and the authentication database.
Sustainability and Conservation
Because wild Aquilaria has been so heavily harvested, agarwood-producing species are listed under CITES, which regulates international trade in the wood. This is one reason cultivated, plantation agarwood has grown — and why a reputable seller should be able to say where the wood came from and whether it was cultivated or wild. Scarcity, regulation, and demand together drive the price; they also make provenance a real, not academic, question for a buyer.
Buying Agarwood: A Practical Checklist
For a first purchase, keep the checks small and concrete:
- Ask the species and origin. If the seller cannot name both, treat that as a signal, not a deal-breaker, but a signal.
- Cultivated or wild? Both are legitimate; the price and expectations differ sharply.
- Smell it warm, not just cold. The honest test is aroma on gentle heat, not the room-temperature first sniff.
- Watch the price. A very cheap “agarwood” or “oud” is almost certainly not agarwood.
- Confirm before you pay large amounts. For anything expensive, laboratory or reputable-seller verification is the reliable route.
Common Mistakes
- Thinking all agarwood is the same. 奇楠 and ordinary 沉香 are materially different (oil-wraps-wood vs wood-wraps-oil).
- Believing the TCM phrases as proven medicine. They are historical, not clinical.
- Buying on price alone. Cheap “agarwood” is almost certainly adulterated or substituted.
- Expecting a strong room-filling burn. Top agarwood is traditionally appreciated by gentle, often flameless heating (隔火焚香), not a big smoky burn.
The Author’s Take
Position: My advice to a beginner is not to learn grading — it is to buy from someone who can name the species and origin without hesitating.
Reasoning:
- The price gap between real and fake agarwood is enormous, so honesty is where the risk concentrates.
- Grading is for after you have found an honest seller; before that, you are grading the seller’s confidence, not the wood.
This is the author’s editorial view and experience — not a verified fact.
Verification Notes
- Botanical identity (Aquilaria sinensis, A. malaccensis) and resin-formation mechanism are standard botanical facts.
- The 奇楠/沉香 “oil-wraps-wood vs wood-wraps-oil” distinction and the 沉水 grading are drawn from Chinese specialist sources; they are traditional grading frameworks, not laboratory standards.
- The 奇楠 etymology is explicitly uncertain — this page states “multiple theories,” not a settled answer.
- The 奇楠 color hierarchy is treated as traditional and possibly non-distinct; sources conflict.
- No therapeutic claims are made.
See The Complete Incense Scent Guide: Choosing a Scent by Atmosphere for the full guide.
FAQ
Q: What’s the difference between agarwood and sandalwood?
Agarwood is resin-impregnated Aquilaria wood — deep, resinous, and sweet — formed as a stress response over years to decades. Sandalwood is Santalum heartwood — creamy, sweet-woody, and smooth. They are different trees, different families, and different aromas. Agarwood is generally the more precious and more heavily faked of the two, with a whole grading system (沉水, 奇楠) built around resin density. Sandalwood’s character is consistent and approachable; agarwood’s is layered and develops in stages as it warms. See the sandalwood guide.
Q: What is 奇楠 (kyara)?
The top grade of agarwood, distinguished by “oil wraps wood” (油包木) — the fiber is so thoroughly resin-transformed that the material is soft and pliable, described as shaving into curls and kneading into pellets, and aromatic even at room temperature. Ordinary 沉香 is “wood wraps oil” (木包油): hard wood with resin veins running through it. 奇楠 is further subdivided by color into traditional grades (white, green, purple, yellow, black), a hierarchy sources treat as traditional rather than settled taxonomy. Japanese “kyara” is the cognate term.
Q: Why does some agarwood sink and some float?
Resin density. The name 沉香 means “sinking fragrance” precisely because the most resin-saturated pieces are dense enough to sink in water, while less-resinous wood floats. This is the backbone of the classical 沉水 grading system: sinking material is the highest grade, half-sinking is medium, and floating is lower. The logic is direct — resin is denser than wood — which is also why the sink test alone is not proof against oil-injection fakes engineered to sink.
Q: How do I know agarwood is real?
Confirm with a reputable seller, and prefer laboratory or documented verification for anything expensive. Traditional signals, which are heuristics rather than proof, include white smoke with oil seepage when burned (fakes often give black smoke), a complex sweet aroma on gentle heat rather than a “burnt wood” or one-note “perfume” smell, and the absence of any synthetic perfume note. A very low price on a prestige grade is itself a strong warning sign. See the authentication database.
More Questions Answered
Q: What does agarwood (沉香) smell like?
Deep, sweet, and resinous, with a woody base — and it develops in stages as it warms: an opening (头香), a body (本香), and a dry-down (尾香). The character is often described as warm and enveloping rather than sharp. High-grade 奇楠 is aromatic even unheated, at room temperature; ordinary agarwood needs gentle heat to release its full character. That staged, layered quality is the opposite of a flat, single-note fragrance, and it is one reason agarwood rewards slow, flameless appreciation rather than a fast smoky burn.
Q: Why is agarwood so expensive?
It forms slowly and unpredictably — over years to decades, and only after a tree is wounded or infected — and wild resources have been heavily depleted, with agarwood species now regulated under CITES. Scarcity, slow formation, heavy demand, and the difficulty of verification all push prices up. Ordinary medicinal-grade chips are comparatively cheap (a few RMB per gram in the Chinese herb market), but dense 沉水 material and especially 奇楠 reach very high prices. The spread between grades is enormous, which is exactly why the market attracts fakes.
Q: Is agarwood the same as oud?
Largely yes. “Oud” (also “oudh”) is the Arabic and Middle-Eastern name for the same resin-impregnated Aquilaria wood called 沉香 in Chinese and jinkō/kyara in Japanese. They are the same material family under different names and different traditions, with different grading vocabularies. The practical caution is the same across all of them: “oud” at a low price, or sold without species and origin, is a common place for adulteration and synthetic substitutes to hide, because the real material is scarce and expensive.
Q: How do I burn agarwood chips?
The refined method is indirect heat (隔火焚香): bury hot charcoal in ash, place a thin mica or metal plate on top, and rest the chip on the plate so it releases aroma without burning. A purpose-built electric incense heater works too and is easier to control. Direct burning is possible but wastes the subtle top notes — the flame destroys exactly the delicate opening stage that makes good agarwood worth appreciating slowly. Match the method to the material: gentle heat for fine agarwood, direct burning for everyday blends.
Q: How can I tell if agarwood is fake?
Traditional signals, as heuristics rather than proof: genuine agarwood tends to give white smoke with oil seepage when burned (fakes often give black smoke), a complex sweet aroma on gentle heat rather than a “burnt wood” or one-note “perfume” smell, and resin-dense pieces that sink in water. But the strongest signal is commercial: a very low price on a prestige grade, or a seller who cannot name the species and origin. For anything expensive, laboratory or documented seller verification is the reliable route, not these heuristics. See the authentication database.
Sources
- Flora of China — Aquilaria genus entry (botanical identity).
- Naef, R. — The volatile and semi-volatile constituents of agarwood (review), Flavour and Fragrance Journal. DOI.
- CITES Checklist — Aquilaria listing (trade regulation status).
- 本草纲目 — historical materia-medica record (traditional, not clinical). Full text on Wikisource.
- 周嘉胄《香乘》(Ming) — agarwood grades and substitutes. Full text on Wikisource.
- Chinese specialist sources on 奇楠 grading and authentication (consumer/specialist tier).
- Research synthesis: docs/research/agarwood-chenxiang-notes.md (R-001).
Related Resources
Natural next step: agarwood is often appreciated by gentle, flameless heating — learn the technique in what Chinese incense is, or compare its smoother cousin in the sandalwood guide.