Complete Guide to Agarwood Material Classification: How to Distinguish Bantou, Chonglou, Kezi, and Laoliao

Agarwood material classification in the trade is based on "how the resin formed," not on a ranking of quality.Terms like bantou, kezi, chonglou, and diaokou describe where on the tree the agarwood resin formed and theshape of the wound—whether it is a trunk break, a branch break, or an insect-bored hole. Different locations mean different resin flow, appearance, aroma style, and what finished products can be made. Learn this set of jargon thoroughly first, then discuss price and authenticity, so you won't get confused by the terminology.

Key Points

• The first cut in agarwood material classification is "tree-heart oil / edge-bark oil": tree-heart oil forms only when the wound reaches deep into the wood, while wounds only on the bark surface produce thin flake-like edge-bark oil.
• Bantou, kezi, chonglou, diaokou, and jujia are the five categories named byresin formation morphology, unrelated to grade; each has top-quality pieces and each has junk.
• Bantou is divided into three grades by the degree of weathering on the cut surface:new head(light color, loose texture) →old head(dark color, hard texture) →iron head(extremely hard texture, dark brown nearly black).
• Daolia, shuichen, tuchen, and tuoluo refer to theburial environment after the incense body separates from the tree, belonging to the category of "mature resin" (shujie).
• Laoliao and xinliao are not concepts of age, but ofmoisture content and aroma stabilityConcept: old material is fully dried and its aroma profile is stable; new material carries moisture and will change after a few years.
• Wild populations of agarwood are listed in CITES Appendix II; cross-border trade requires permits, and when buying wild material, make sure the source is compliant.

1. The first cut in classifying agarwood material: heartwood oil vs. edge-bark oil

Heartwood oilrefers to agarwood formed when a wound reaches deep into the inner wood of the trunk. Inside the wood, sap is abundant and nutrients are rich, so the resin produced is dark in color and high in density; the oil lines are dense and mostly black oil, and when the oil ratio is high enough, it reaches "sinking grade." The vast majority of fine material on the market that can be turned into beads or carved into ornaments comes from heartwood oil.

Edge-bark oilrefers to agarwood formed when a wound stays only on the surface of the bark and does not reach the inner trunk. The resin travels along the vessels on the bark surface and adheres to the surface, forming thin flakes; the oil deposit is thin and it is hard to form a substantial aromatic body. Edge-bark oil is further divided into two types: the type close to the woody part is calledrow oil(resin distributed evenly in lines along the vessels), and the type formed directly on the bark is calledbark oil(with a bark-like texture, rarer than row oil).

Remember it in one sentence:the deeper the wound, the better the oil; the shallower the wound, the thinner the incense.This is also why, within the same producing region and the same tree species, prices can differ several times over.

2. Classification by wound form: ban tou (flat cut), shell, insect hole, hanging mouth, saw clamp

This group covers the terms most often heard in the market and also the easiest to buy wrong.

Ban tou (flat cut): agarwood from the flat surface of a trunk break

When an agarwood tree is sawed off, cut down, or broken by wind while the tree is still alive, the agarwood formed on the cross-section of the break is calledban tou. Because the wound cuts across the tree body, the oil lines of ban tou are not linear along the vessels but appear asdots and surface patches—this is the most recognizable feature of ban tou; when the cross-section is cut open, individual oil dots can be seen.

Ban tou is generally flat overall with irregular edges; it is not thick, but the resin can be very dense. Based on the degree of weathering of the cross-section, the trade further divides it into three grades:

From new head to iron head, the darker the color, the harder the texture, the better the quality, and the price goes up all the way.

Wrap headIt is a variant of flat head: the area around the break is completely wrapped by newly grown bark, indicating that the tree lived for a long time after breaking and wrapped the incense inside. Wrap head incense is usually more mellow.

Shell (shell sinking): ear-shell shape at the broken end of a branch

After a branch breaks and falls, shell-shaped agarwood forms at the break, called in jargonshell, also known as shell sinking, shell zai, tree ding, tree ear, bamboo hat, oil cap. Its formation principle is similar to flat head, but the cross-section is uneven and the incense body is thin, so it cannot form a flat surface like flat head, but curls into an ear shell.

Shells are generally thin and cannot be made into large pieces, but they have the advantage of complete shape and clean aroma, and are commonly used materials for making incense seals, incense powder, and electric incense burners.

Worm hole (worm eye, ant sinking): spiral incense centered on worm tunnels

The incense formed after an agarwood tree is eaten by insects is calledworm hole, also called worm eye. The insect bites a tunnel horizontally or diagonally, and the resin forms a spiral incense body centered on the worm tunnel, with a peculiar shape,at least one worm eye can be found on every piece of worm hole, which is its most recognizable identity mark.

There is a general saying about the aroma: the one with stronger sweetness and more mellow is calledAnt agarwood(also often called honey incense); the one with a heavier cooling note is called wormhole.

One reminder here:artificial wormhole is not bitten by insects. Some use steel rods to punch holes to encourage incense; the wormholes are large, the incense-forming time is short, and the oil is scarce, so the scent is far inferior to wild wormhole, and the price should be a different matter. When buying wormhole, look at the size of the wormholes and the direction of the oil lines, not just the shape.

Hanging mouth and saw clamp

Hanging mouth, agarwood formed after the tree surface is cut and wounded, locally thread-like.Saw clamp, there are saw marks on the tree, and the oil is secreted and formed around the saw marks. Both types are not large in quantity, so it is enough to "recognize them when you see them".

III. Classified by burial environment: fallen rack, water sinking, earth sinking, shed

The previous group talked about where the incense grows; this group talks aboutwhere the incense stays after it leaves the tree. This category is collectively called "mature formation" in the trade.

• Fallen rack: the incense body is still in the tree, but the tree is already dead, lying fallen in soil or swamp; the woody part decays and weathers under the action of microorganisms and the environment, and the oil-bearing part does not decay or weather and remains, shaped like a fallen rack.
• Water sinking(water grade): after the incense body leaves, it falls into moist mud or swamp and matures in water. The color is rather black; because of water protection, weathering is not severe, and the oil lines are clearly discernible; the texture is hard and tough, and the incense body is thick and solid.
• Earth sinking(underground grade): it falls into dry mud with little water content and slowly weathers and matures, forming a loose and porous texture. The surface color changes with the soil, so there are distinctions of "red earth" and "black earth".
• Shed / dead wood sinking / dead chick: after the tree dies, the oil-bearing part precipitates and ferments for a long time, and the color becomes lighter and gray; it belongs to the fallen rack line.

The common point of mature formation material ismellow fragrance and little dry qi, because the woody part has already been eliminated by time. Fresh formation (collected from living trees) often carries a bit of raw wood qi.

IV. Gousi, white wood, wood blank: three terms in the processing chain

These three terms are not types of incense material, butprocessing stagesterms that buyers often encounter and must understand.

• White wood: raw Aquilaria sinensis material that has not formed agarwood, containing no oil.
• Wood blank: raw material that has already formed agarwood but has not yet had the white wood removed.
• Gousi: when removing the wood blank, the wood shavings hooked off with a small iron hook from the part tightly attached to the oil layer, sitting between oil-bearing and oil-free.

Gousi is cheap and is a common material for boiling water, soaking in liquor, and making low-priced incense sticks. Butgousi is not equal to finished agarwood, its oil content is extremely low; do not compare the price of gousi with the price of sinking-grade material—and do not do the reverse either, selling gousi as finished agarwood at a high price. In the shop we often meet incense enthusiasts bringing a string of "beads pressed from gousi" for appraisal; that thing smells fragrant, but it is not actually agarwood beads.

V. Old material and new material: not about years, but stability

The terms "old material" and "new material" are the most overused, and they are also the pair in this batch of classifications that most needs to be clarified.

Old material, refers to material that has been stored for many years after harvesting, with moisture fully gone and fragrance stable. Characteristics: light in hand (relative to new material of the same volume), fragrance not dull, does not crackle on the burner, does not absorb moisture again. The fragrance profile of old material is basically fixed; it smells like this today, and still like this three years later.

New material, refers to material harvested recently with high moisture content. Characteristics: heavy in hand, fragrance carries moisture and a raw green note, and it easily produces off-notes on the burner. If new material is stored in the right place (ventilated, away from light, not sealed and stuffy) for three to five years, it will gradually take on the texture of old material.

So when judging old material versus new material,look at moisture content and fragrance stability, not the number of years the seller claims. If the other party says "thirty-year-old material," ask whether you can weigh it in hand and test a piece on the burner—light in hand and pure on the burner, that is the real test.

VI. What different forms are suitable for

Before buying, first think clearly about the use; choose the wrong form and half your money is wasted.

VII. The shopkeeper's three purchase recommendations

First identify the form, then discuss the production area, and only then the price.The order is reversed, and it's easy to be led astray by big terms like 'Hui'an family' and 'Nha Trang'. A piece of sinking-grade heartwood oil from Xingzhou is much more expensive than a thin shell from the Hui'an family, and reasonably so.

Buy according to use.If you want to burn incense, buy incense materials like board ends and shells, which offer the best value; if you want to make beads, you must buy sinking-grade heartwood oil material, as the yield of making beads from board ends is frighteningly low. Last year, a fragrance friend, Lao Chen, bought three jin of board ends to make bracelets to save money, only to find after cutting that the oil layer was just a thin layer, with a yield of less than 10%, and finally all was ground into powder for burning—the powder is good to use, but that money could have been spent more wisely.

Price range reference (subject to market fluctuations, for reference only): Daily incense materials (shells, edge oil, combed threads) are about tens to hundreds of yuan per gram; mid-range materials like board ends and insect-hole pieces are about several hundred to two thousand yuan per gram; old sinking-grade heartwood oil material is usually several thousand yuan per gram and up, and wild sinking-grade collectible material starts at 6,000–12,000 yuan per gram. For 'fire-sale prices' across ranges, ask why first.

Can't tell if the material in your hand is board end or heartwood oil, old or new? Bring the goods to the store, and the shopkeeper will help you take a look for free; if it's inconvenient to go out, call400-809-1913, and send a few photos of the cross-section, and we can also get a rough idea.

Eight, compliance reminder

The genus Aquilaria (Aquilaria) wild populations are listed in CITES Appendix II, and cross-border trade requires import and export permits for customs clearance. For domestic purchase of wild material, identify suppliers who can provide source and compliance documentation; there are also limits on personal carry when leaving the country, so don't take chances. This point is also mentioned in'Why Agarwood Is Expensive'—compliance costs are real costs, and also part of the price difference between genuine goods and 'three-no' bulk goods.

The jargon of incense material classification is, in the end, the experience accumulated by incense collectors over centuries: one word is a history of resin formation. Once you know them all, your eye for a piece of material will be different.

Frequently Asked Questions

Which is the best among board ends, insect-hole pieces, and shells?

There is no absolute 'best'; the three are different resin formation forms, not grades. Board ends win with dense oil and large flat surfaces, suitable for slicing and burning; insect-hole pieces have unique shapes and are also ornamental; shells are thin and clean, and the most economical to grind into powder. Under the same production area and oil content, board ends usually have the highest unit price because they can be cut into regular large slices of incense material. To judge quality, return to the three hard indicators: oil content, production area, and fragrance charm.

Is old material always better than new material?

In most cases, yes, but not absolutely. The advantages of old material are low moisture content, stable fragrance charm, and no off-flavors when heated; if new material itself has high oil content, good production area, and proper storage environment, it can reach a comparable level after three to five years. Note that the term 'old material' is seriously overused; the basis for judgment is the weight in hand, purity of aroma, and performance when heated, not the merchant's claim of years.

Are larger insect holes on insect-hole pieces better?

No. Wild insect-hole pieces are insect tunnels bitten by insects, with fine insect holes, oil lines distributed spirally along the tunnels, and long resin formation years; artificial insect-hole pieces often use steel rods to punch holes, with obviously larger insect holes, short resin formation time, less oil, and thin aroma. Larger insect holes may instead be a sign of artificial stimulation. When buying insect-hole pieces, comprehensively look at the direction of oil lines, aroma thickness, and insect hole morphology, and don't be moved by peculiar shapes alone.

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