Brazilian rosewood, also called jacaranda, is perhaps one of the most beautiful woods in the world. However, extensive harvesting over the past three centuries has virtually eliminated this tree from the Brazilian forests, so that today it is not supposed to be harvested. The only material that can be sold legally is old stock; such material has to display a CITES Certificate, noting special approval. As might be expected, the wood is extremely expensive.
The tree is classified as Dalbergia nigra. Two other trees in this genus are D. retusa, commonly called cocobolo, and D. stevensonii, called Honduras rosewood. In fact, Honduras rosewood, which is also a rare species, is considered a substitute for Brazilian rosewood; Honduras rosewood is highly desired for making marimbas and xylophones. Another substitute is Santos rosewood (also called Santos mahogany) which is classified as Machaerium scleroxcylon.
The Brazilian rosewood tree sometimes attains a height of 125 feet, and a diameter up to 4 feet; most trees are smaller. Old defective stems yield the most attractive wood grain and color. Incidentally, the rosewood name comes from a strong rose-like smell when the lumber is sawn; the aroma can sometimes be noted in the dried lumber as well.
Rosewood has been used for centuries in solid and veneer form for beautiful furniture, pianos, parquet flooring, instruments, tool and knife handles, wood sculpture, carving and turnery. Most recently, this wood was prized for use in guitars due to its extreme resonance and for producing full tones, with deep basses and brilliant trebles. Guitar makers still revere this wood.
Processing suggestions and characteristics
Density. The density of dried material ranges from 50 to 60 pounds per cubic foot. A dry piece of lumber weighs close to 5 pounds per board foot. It is so heavy that it will barely float in water.
Drying. As with most high density woods, drying is done slowly to prevent checking. Shrinkage in drying is very small...about 3.6 percent.
Gluing and machining. Gluing is not easy due to oils in the wood. Freshly prepared surfaces are essential. Cleaning the surfaces with a solvent is prudent. Its high density also means that surfaces must be exceptionally flat and true.
Machining, as with all high-density woods, requires very sharp tools. Machined surfaces are very smooth. Slow feeds produce rubbing and heat; higher speeds require power and can produce chip-out. Close attention to feed speeds is necessary.
Stability. Dried rosewood is extremely stable, requiring a change of 6-1/2 percent MC to result in a 1 percent size change tangentially (across the width of flatsawn lumber). Radially (across the width of quartersawn lumber), a 10 percent MC is required to result in a 1 percent size change. Certainly this stability is a big factor in the excellent performance of rosewood furniture that is exposed to varying environmental conditions.
Strength. As might be expected from its density, rosewood is fairly strong and stiff. The ultimate strength (MOR) is 19,000 psi. The stiffness (MOE) is 1.88 million psi. The hardness is 2,720 pounds (much harder than any U.S.-grown wood). For comparison, northern red oak values are 14,300 psi, 1.82 million psi and 1,290 pounds.
Color and grain. The sapwood is white and is always considered waste. The heartwood is various shades of brown to chocolate or violet irregularly and conspicuously streaked with black. Often the wood has an oily or waxy feel.
The grain is straight and medium to coarse in texture.
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