Sinking Agarwood vs. Semi-Sinking Agarwood: A Scientific Guide to Density, Oil Content, and Hand Feel

Sinking Agarwood vs. Semi-Sinking Agarwood: A Scientific Guide to Density, Oil Content, and Hand Feel

When buying agarwood, one often hears the terms "sinking grade," "semi-sinking," and "non-sinking." Behind this is actually a density issue, not mysticism.

I. Where Does Buoyancy Come From?

The density of water is approximately 1.0 g/cm³. Whether a piece of agarwood sinks depends on whether its average density is greater than that of water. The density of agarwood consists of two parts:

• **Wood matrix**: The density of white wood (the non-resinous portion) is usually less than that of water;
• **Aromatic resin (oil)**: The density of agarwood resin is greater than that of water.

When the oil content is sufficient and the overall average density > 1.0, it "sinks"; when slightly below that of water, suspended in water, or slowly sinking, it is called "semi-sinking"; when clearly lighter than water, it floats on the surface.

> In short: the more oil, the more it sinks; sinking or not is approximately an intuitive gauge of oil density (but note this is a necessary, not sufficient, condition—see the misconceptions below).

II. Hand-Feel Assessment Method (Verifiable)

| Dimension | High-Oil Agarwood (tending to sink) | Low-Oil White Wood (tending to float) |
|---|---|---|
| Weight | Clearly heavy in hand for the same volume | Light and buoyant |
| Temperature | Warm and smooth to the touch, slow heat conduction | More "woody," cool and light |
| Cut/Cross-section | Clear oil lines, strong resinous feel | Dry and astringent, strongly fibrous |
| Aroma | Stable aroma profile at room temperature | Faint aroma only after rubbing to warm |

III. Three Common Misconceptions

1. "Sinking = genuine": Wrong. Some pressed, oil-injected, or high-density imitations can also sink. Sinking is only a density clue, not a criterion for authenticity.
2. "Non-sinking = inferior": Not necessarily. Some light materials with excellent aroma are used for incense and medicine, and their value does not lie in sinking.
3. "Semi-sinking = defective": Semi-sinking is often a cost-effective choice—its oil content is already not low, yet its price is far below sinking grade.

IV. The End of Science Is Traceability

For collectors and traders, the most reliable approach remains test certificates + origin traceability (e.g., GC-MS comparison of gas chromatography fingerprint profiles). Buoyancy and hand feel are entry-level screening tools; certificates are the "hard currency" for grading and pricing.

> Science note: This article provides an overview of general consensus in academia and industry; specific values vary by tree species, origin, and resin formation method. For citation, please refer to the latest peer-reviewed literature and authoritative testing.