Macassar Ebony for Custom Wood and Epoxy Tabletops
Macassar Ebony, recorded in the CIRAD Tropix technical sheet under the French trade name Ebène Veinée d’Asie, represents a group of dense ebony species native to Asia-Oceania. These include Diospyros celebica, Diospyros marmorata, Diospyros rumphii, and Diospyros p.p. Unlike uniformly black African ebonies, Macassar Ebony is famous for heartwood that is dark brown to black, patterned with irregular stripes of reddish brown or gray-brown tangential veins. With its fine texture and slight interlocked or straight grain, it yields a striking contrast when paired with clear or tinted casting resins.
Building an epoxy river table or wide conference top with Macassar Ebony requires a thorough understanding of its physical weight, moisture behavior, and cutting resistance. The technical data published by CIRAD Tropix provides the necessary baseline for handling this dense hardwood safely in the shop.
Density, Hardness, and Mechanical Strength
Macassar Ebony is exceptionally heavy. At 12% moisture content, it features a specific gravity of 1.20, translating to a density of about 74.9 lb/ft³. A 2-inch-thick slab weighs roughly 12.5 lb per square foot. The CIRAD Tropix sheet notes that this wood does not float in water, meaning custom bases must be constructed to handle substantial static loads.
When assessing tabletop durability, European technical sheets often report surface hardness using the Monnin hardness test. Monnin hardness is measured on a French scale where higher numbers reflect greater resistance to indentation and a harder surface (it must never be converted to a Janka value). For Macassar Ebony, the CIRAD Tropix data sheet leaves the Monnin hardness unrecorded, though its mechanical strength profile is formidable: crushing strength reaches 70 MPa (about 10,150 psi), static bending strength measures 250 MPa (about 36,260 psi), and modulus of elasticity is 18,000 MPa (about 2,611,000 psi).
Dimensional Shrinkage and River Table Stability
Any hardwood embedded alongside rigid epoxy resin experiences dimensional movement as relative humidity changes. CIRAD Tropix measures total tangential shrinkage at 7.7% and total radial shrinkage at 3.4%. This yields a tangential-to-radial shrinkage ratio (St/Sr) of 2.3.
Because the St/Sr ratio is 2.3, flatsawn boards will experience significantly more seasonal movement across their width than quartersawn sections, introducing a moderate tendency toward cupping if moisture changes drastically. To prevent shear stress along the wood-to-epoxy bondline, the timber must be brought down to equilibrium moisture content before pouring resin. CIRAD notes that heartwood treatability falls under Class 4 (not permeable), meaning deep epoxy penetration into the cellular structure will be minimal.
Slab Width Potential and CITES Regulations
Makers planning wide river tables should review log dimensions. CIRAD reports tree trunk diameters from 30 to 60 cm, with sapwood thickness spanning from 7 to 10 cm. Because the sapwood is clearly demarcated—showing yellowish-white, pink-grey, or pale reddish-brown tones against the dark heartwood—builders can incorporate live edges with sharp visual contrast. However, the modest log diameter means wide, single-slab tops are rare; river tables generally require bookmatched boards, multi-board glue-ups, or narrower side slabs.
Regarding trade restrictions, CITES Appendix II (under the Washington Convention 2025) lists only Diospyros species originating from Madagascar for logs, sawn wood, and veneer. True Macassar Ebony harvested from Asia-Oceania is not included under that specific Madagascar CITES Appendix II listing.
Pros and Cons for Epoxy Tabletops
- Pros: Stunning natural figure featuring black heartwood with reddish brown or gray-brown veins; Durability class 1 (very durable against decay fungi) and Class D resistance against termites and dry-wood borers; extreme mechanical strength (static bending strength of 250 MPa); fine texture creates clean edges along resin rivers.
- Cons: Slabs are narrow due to modest log diameters (30 to 60 cm); heavy weight (about 74.9 lb/ft³) requires robust table bases; high risk of checking during drying; fairly high tool blunting requires carbide and stellite tooling; pre-boring is mandatory for table mounting hardware.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Diospyros celebica, Diospyros marmorata, Diospyros rumphii, Diospyros p.p. | |
| Colour / texture / grain | Dark brown; texture fine; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 1.20 | about 74.9 lb/ft³; a 2-inch-thick slab weighs about 12.5 lb per sq ft |
| Total tangential shrinkage | 7.7 % | green to oven-dry |
| Total radial shrinkage | 3.4 % | green to oven-dry |
| Ratio St/Sr | 2.3 | closer to 1 = less cupping tendency |
| Thermal conductivity | 0.38 W/(m·K) | |
| Crushing strength (12% MC) | 70 MPa | about 10,150 psi |
| Static bending strength (12% MC) | 250 MPa | about 36,260 psi |
| Modulus of elasticity (12% MC) | 18,000 MPa | about 2,611,000 psi |
| Decay (fungi) resistance | Durability class 1 – very durable | |
| Termite resistance | Class D – durable | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 4 – not permeable | |
| Use class from natural durability | Class 4 – in ground or fresh water contact | |
| Drying | rate slow; distortion: slight risk; checking: high risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 45–65 °C | about 113–149 °F |
| Machining | blunting fairly high; saw teeth: stellite-tipped; cutting tools: tungsten carbide | |
| Nailing and screwing | Good but pre-boring necessary | |
| CITES status | Only Diospyros from Madagascar are listed in CITES Appendix II (Washington Convention 2025). The products concerned are logs, sawn wood and veneer. |
Values from the CIRAD Tropix technical sheet (average values for mature wood, 12% moisture content where noted). US-unit conversions are calculated by BigEpoxy (1 MPa = 145.04 psi; density = specific gravity × 62.43 lb/ft³).
Shop Notes for Building with Macassar Ebony
Slab Selection and Live Edges
Evaluate boards for heartwood figure and intact sapwood. The sapwood band is 7 to 10 cm wide and offers a light yellowish-white to pale reddish-brown counterpoint to the dark heartwood. Check all surfaces for fine cracks, as this species carries a high risk of checking during seasoning.
Drying Considerations
Drying rate is slow. While the risk of distortion is slight and there is no known specific risk of casehardening or collapse, checking remains a severe risk. Suggested kiln program temperatures run between 45 and 65 °C (about 113 to 149 °F). Slabs must be dried slowly to avoid surface and end checks before resin fabrication.
Machining and Pre-Boring
Macassar Ebony exerts a fairly high blunting effect on cutter heads. Saws should use stellite-tipped teeth, and shaping tools require tungsten carbide cutters. Machining and sanding dust can cause respiratory or skin irritation, requiring strict dust collection. Fastening table legs requires pre-boring; driving screws without pilot holes will snap fasteners or split the dense timber.
Gluing, Sealing, and Resin Pours
Because of its very high specific gravity (1.20), CIRAD notes that gluing must be executed strictly according to standard codes of practice. Clean the contact edges thoroughly before assembly. Because the heartwood is impermeable (Class 4), apply a thorough epoxy seal coat along the live edges to close off surface pores and mitigate outgassing bubbles before the main deep pour.
Sources
- CIRAD Tropix 7 technical sheet: Macassar Ebony (Ebène Veinée d’Asie)
- CIRAD Tropix 7 technical sheets (index)
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: While modern shops primarily use Macassar Ebony for high-class cabinetwork and musical instruments, the CIRAD Tropix sheet also documents its traditional service in tool handles for resilient woods, sculpture, turned goods, and wood-ware thanks to its extreme bending strength. (Source: CIRAD Tropix 7 technical sheet: Macassar Ebony (Ebène Veinée d’Asie).)