Wood species
Brazilian rosewood wood
Brazilian rosewood is a hardwood (Dalbergia nigra). At 12% moisture content it has a Janka hardness of 2,720 lbf (12,099 N) and it weighs about 59 lb/ft³ (944 kg/m³), 4.9 lb (2.23 kg) per board foot.
Also called: jacaranda.
Key numbers
- Janka hardness, 12% MC
- 2,720 lbf (12,099 N)
- Green: 2,440 lbf (10,854 N)
- Weight at 12% MC
- 59 lb/ft³ (944 kg/m³)
- 4.9 lb per board foot
- Specific gravity (oven-dry weight)
- 0.80 on green volume
- Shrinkage, green to oven-dry
- 4.6% tangential
- Radial 2.9%, volumetric 8.5%
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4)
Why: From the USDA Wood Handbook, which collected these values from the world literature; Brazilian rosewood's density is worked from its specific gravity with the Handbook's own equations.
How much Brazilian rosewood moves
A 12 in wide flatsawn board of brazilian rosewood that goes from 6% to 12% moisture content swells about 0.11 in (about 1/8 in, 2.9 mm). Quartersawn, the same board moves about 0.07 in (about 1/16 in, 1.8 mm). Flatsawn faces move 1.6 times as much as quartersawn ones, because the wood shrinks 4.6% around the growth rings but only 2.9% across them.
Worked from the Wood Handbook's shrinkage values (Table 4-4) with its Eq. 13-4; the Handbook gives no movement coefficients for imported woods. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Shades of brown, red and violet, irregularly streaked with black; white sapwood.
- Grain and texture
- Coarse texture, generally straight grain, with an oily or waxy look and feel and a fragrant smell.
- Working and character
- Hard and heavy; air-dry wood barely floats. Harder than any US hardwood used for furniture. Machines and veneers well; glues with care because of its oil.
- Uses
- Mostly decorative veneer; solid pieces for cutlery handles, brush backs, cue butts and turnery.
The Handbook reports that Brazilian rosewood is listed in CITES Appendix I, so international commercial trade is prohibited.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-35.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Values for brazilian rosewood from Wood Handbook Table 5-5b (p. 5-24), which the Handbook says were collected from the world literature, on clear, straight-grained specimens. Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 14,100 psi (97 MPa) | 19,000 psi (131 MPa) |
| Stiffness (MOE) | 1,840,000 psi (12.7 GPa) | 1,880,000 psi (13 GPa) |
| Crushing strength (compression parallel to grain) | 5,510 psi (38 MPa) | 9,600 psi (66 MPa) |
| Shear parallel to grain | 2,360 psi (16 MPa) | 2,110 psi (15 MPa) |
A dash means the Handbook prints no value; none is filled in.
Dust and health
- Wood dust is classed as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer, chiefly for cancers of the nose and sinuses.
- NIOSH recommends keeping wood dust exposure to 1 mg/m³ of total dust, as quoted in OSHA's sawmill guidance.
- Germany's federal list of sensitizing substances (TRGS 907) names Dalbergia nigra as a skin sensitizer.
This is what the named authorities publish, not medical advice.
Compare with
Why these numbers
Why these numbers?
The situation
The Wood Handbook prints 2,720 lbf of side hardness at 12% moisture content for brazilian rosewood, a value it says was collected from the world literature (Table 5-5b, p. 5-24).
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
What that means
Side hardness (Janka) is the load needed to press a 0.444 in (11.28 mm) steel ball halfway into the wood across the grain; a higher number dents less (Handbook p. 5-5).
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
So
The Handbook gives only the green specific gravity (0.80) for brazilian rosewood, so it is moved to 12% with the volumetric shrinkage of 8.5% (Eqs. 4-9 and 4-11), then multiplied by water's density and 1.12 (Eq. 4-14).
Arithmetic: exact by definition , sources [1]
The number
About 59 lb/ft³, or 4.9 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources