Tonka-Bean

A dense, exceptionally durable hardwood known for strength, stability, and long‑term performance.

Common Name(s): Tonka Bean, Cumaru, Brazilian Teak

Scientific Name: Dipteryx odorata, Dipteryx spp.

Distribution: Guyana, Suriname, Brazil, Northern Amazon Basin

Tonka-Bean — also known as Cumaru — is an ultra‑dense, high‑performance tropical hardwood prized for its exceptional hardness, durability, and resistance to decay. Native to Guyana and the wider Amazon region, Tonka Bean is widely used in decking, heavy exterior structures, industrial flooring, and long‑life architectural applications. Its rich brown colour, fine texture, and high mechanical strength make it one of the toughest commercial hardwoods available. With proper machining and finishing, Tonka Bean delivers decades of service even in harsh tropical or marine environments.

Key Attributes

Appearance

Colour

Medium brown to dark reddish‑brown

Grain

Interlocked, sometimes wavy

Texture

Fine to medium

Density

Extremely heavy

Performance

Workability

Difficult (very dense + interlocked grain)

Durability

Exceptional

Stability

Excellent dimensional stability

Technical Information

Property	Value
Janka Hardness	3,200 lbf
Modulus of Rupture	22,000–25,000 psi
Modulus of Elasticity	2,700,000–3,000,000 psi
Density	65–75 lbs/ft³ (avg ~70)
Crushing Strength	12,000–14,000 psi
Shrinkage (Radial)	4.5%
Shrinkage (Tangential)	7.8%
Shrinkage (Volumetric)	12.3%
T/R Ratio	1.7
Workability	Difficult (extreme density + interlocked grain)
Planing	Fair; tear-out possible
Sanding	Good
Finishing	Accepts oils; UV oils recommended outdoors
Stability	Excellent dimensional stability
Durability	Exceptional (decay, insects, marine borers)
Moisture Movement	Low