THE ROSEWOOD JUNGLE
by Dick Boak, manager of the Wood Division of Martin Guitar Company, visit http://www.mguitar.com/.
Rosewoods in general have been prized throughout history because of their richly exotic and vividly contrasting grain. In terms of sheer beauty, few woods can compete with Rosewood. There is however, a great deal of confusion and misinformation about the many varieties of genuine Rosewoods as well as the so-called "substitute" species. This article should clear up most of that confusion. In order for a wood to be considered "true" or "genuine" Rosewood, the tree must be a member of the specific genus Dalbergia (Leguminosae family).
There are many species within the Dalbergia genus:
BLACKWOOD (Dalbergia melanoxylon) Africa African Blackwood, also known as Grenadillo or Mozambique "Ebony", is dark purple to black in color with similar density and working properties of true Ebony. It should not be confused with Granadillo, a Rosewood substitute discussed later in this article. African Blackwood is traditionally used in the construction of the finest wind instruments, bagpipes, violin bows, ornamental turnings and precious treen. It is very rare, very expensive and is generally available in small dimensioned pieces only.
BRAZILIAN ROSEWOOD (Dalbergia nigra) Brazil Sometimes referred to as "Jacaranda", this preferred species ranges in color from dark brown to violet with spidery black pigment lines that often overlap giving the illusion of landscape, hence the term "landscape grain". The smell is like roses when freshly cut. Brazilian Rosewood is the optimum species for the reflective back and sides of acoustic guitars. The species was so popular as sliced veneer for the furniture and plywood markets during the first half of the century that it has been driven to near extinction, though some sparse new growth timber has appeared on the market. The highly resinous wood turns beautifully, polishes well and is very durable. It is very expensive if available at all.
COCOBOLO (Dalbergia retusa) Mexico & Central America
This highly exotic wild grained species is brilliant orange, rust, purple and yellow with distinctive superimposed lines of purple and black. The brilliant color seems to oxidize gradually with air exposure after cutting. Some woodworker's react specifically to the cinnomon-like sawdust that typically causes itching or sneezing. Nonetheless, the unusual vivid beauty and color contrast of this wood overshadow the allergic risks. It is typically available in small cuttings due to the relative small size of the tree.
EAST INDIAN ROSEWOOD (Dalbergia latifolia) India Predominantly light to dark purple, with occasional red and brown streaks, East Indian Rosewood is prized for it's consistency and it's size. When Brazilian Rosewood began to become scarce, East Indian Rosewood quickly filled the vacancy. The wood was more stable, met grade lumber specifications easier, and came in larger planks. Within the last ten years, embargoes and regulations have severely limited the sizes of East Indian Rosewood pieces allowed out of India. Some "plantation" growth of the same species is available as "Sonokeling" from Indonesia. Another close relative includes Dalbergia sissoo from the region in and around India.
HONDURAS ROSEWOOD (Dalbergia stevensonii) C. America Honduras Rosewood is pinkish brown to salmon red with dark irregular grain lines. It is very hard, heavy, and durable. It is difficult to dry and prone to heart cracking which causes poor yield, but after drying the wood is quite stable. Honduras Rosewood is highly regarded within the furniture and musical instrument industry for its beauty, its strength and its tone quality. It takes a trained eye to differentiate between Honduras Rosewood and Guatemala Rosewood, Dalbergia tucurensis or Dalbergia cubilquitzensis (two botanical names for the identical species).
KINGWOOD (Dalbergia cearensis) Brazil Kingwood, often referred to as Violetwood, is brownish purple with fine stripes of black and luminous violet that can approach royal blue. Appreciably denser than most other rosewoods, Kingwood is similar to Brazilian Rosewood in technical properties, but harder and stronger. The size of clear cuttings is very small but Kingwood works well and takes a high natural polish. It is especially popular for fancy trinkets and decorative marquetry.
AMAZON ROSEWOOD (Dalbergia spruceana) Brazil Also referred to as "Jacaranda do para" or "spruceana", this species resembles Brazilian Rosewood somewhat and is used for similar purposes, though odor and subtle grain characteristics are noticeably different. The pores are often filled with a characteristic yellow sulphur deposit. The trees are generally logged during Mahogany harvests in the Amazon River region.
TULIPWOOD (Dalbergia frutescens) Brazil Sometimes distributed as "Brazilian Pinkwood", Tulipwood has a rich pinkish golden hue with luminous salmon stripes. The general color is much lighter than any of the other Rosewoods. It is quite valuable and is generally available in small cuttings only.
Sapwood & Wormholes: All of the genuine Rosewoods and many of the common Rosewood "substitutes" have a creamy white sapwood (similar to poplar in texture) which is slightly softer than the dark heartwood and as a result is more prone to attack by insects. When the insects get through the sapwood however, they generally have a very difficult time gnawing at the denser heartwood, so they give up, turn around and exit. For this reason, Rosewoods are considered fairly resistant to insect attack. If there are wormholes at all, they are usually extremely small and fairly close to the bark.
Calcium & Mineral Deposits: Certain growing regions have a high concentration of calcium, sulpher, or other trace minerals in the soil or in the water table. These minerals are drawn up through the roots and deposited into the pore structure and heart of the tree. When the lumber is cut, mineral can cause problems for the sawyer, since deposits can sometimes be substantial resembling crusty rocks in both appearance and hardness. (See photograph of a typical sample of deposited calcium taken from an East Indian Rosewood log during custom cutting) In addition, calcium and other mineral deposits do not register on a metal detector. Once the lumber is cut, mineral deposits can show up as chalky white dots in the pores of the board. Extensive mineral will have a detrimental effect on the sharpness of planer blades and sawteeth. Small deposits can be removed after fine sanding by tedious digging with a needle or small Exacto knife, or they can be chemically neutralized (darkened) with muriatic acid. This will seriously alter the color and grain contrast of Rosewood if applied to the whole surface, so it is important that the acid be carefully applied to each spot with a metal quill pen.
Plantation Growth: It has become viable to grow Rosewood trees commercially, though few countries have actually taken this idea seriously. Plantation growing is, however, seen in Indonesia and other areas of the orient. Sonokeling is the exact genus and species as East Indian Rosewood (Dalbergia latifolia). It is grown in Indonesia instead of India. The visual appearance of these transplanted species is different somewhat than trees grown in their natural wild. Trees grown in regular rows without underbrush or competition for light have wide and even fast growth rings, and their grain pigment is often less rich and diverse, perhaps more pastel, than the more unpredictable wild growth. Nonetheless, plantation growth is easier to harvest and can be replanted on a regular schedule so that the cost and any detrimental environmental effect can be minimized.
Toxicity: Though rosewood is not actually toxic, most of the varieties are classed as potential irritants. Many people who work with certain species (and some of the substitutes) have or acquire an acute allergenic reaction to the sawdust. In some cases, people react to skin contact with itching, rash or hives. Sometimes sneezing or headaches occur from breathing the sawdust. In most cases however there is no reaction. To be safe, wear a dust mask as you should during sanding of any wood species. If you react upon skin contact, you can try a heavy sweatshirt and a pair of rubber gloves, but you might decide to simply not work with that particular variety.
Resin Content: Most all members of the Dalbergia genus have considerable resin content that can cause some problems in the machining, gluing, and finishing processes.
In machining, this resin can gum up sawblades, planer knives, and sanding belts fairly quickly. With blades and knives, this resin can be dissolved by occasional soaking and/or scrubbing in an appropriate commercial solvent. Sanding belts are less easy to clean, though there are belt cleaning systems available for high production situations. With gluing, resins in Rosewood can cause occasional adhesion problems. A strong polyvinyl white glue is most effective. (Titebond works quite well.) It is smart to glue-up immediately (within ten minutes) after machining or sanding. The resins in true Rosewoods can prohibit polyurethane and other oil based finishes from curing. It is best to avoid oil-based finishes on Rosewood. Greater success will be achieved with lacquer. A compatible vinyl sealer is most effective as a first coat in order to hold the resins down. Vinyl is also useful in "sandwiching" mineral spirit based fillers before application of successive lacquer (sanding) sealer and lacquer coats. Rosewoods have a fairly open pore structure. These pores will soak up finish like a sponge unless a filler has been applied. Dark fillers work best on Rosewood, since natural fillers tend to dry white, resembling undesirable calcium or mineral deposits. Solvents in the initial finish coat can often dissolve the resins in Rosewood causing the pigment to bleed or migrate onto adjacent laminates or trim.
The best way to avoid this problem is to mist extremely light coats of sealer until an adequate base has been provided, then successive heavier coats can be sprayed. In some cases it is necessary to mask highly contrasting white woods or seal them with brushed applications of shellac, vinyl sealer, or lacquer sealer. It is also possible to scrape areas clean that have bled, with a single edged razor or sharp scraper, then respray. There have been several homespun methods of dealing with the resin problem through the years. It is possible to "roast" the wood at low temperatures causing most of these resins to bleed up to the surface where they can be scraped or sanded away. This takes a special apparatus built for the purpose (don't try the oven) and there is no substantiated evidence that roasting will solve any of the resin problems. Another practice involves washing the gluing surfaces in advance with acetone. Although some resin might be removed with this method, it is most likely that the acetone will in fact draw deeper resins up to the surface thereby rendering this a useless process.
Weight: The various Rosewoods range in weight from approximately 53 to 75 lbs/cubic foot averaging 60 lbs/cubic foot. This translates to approximately 5 pounds per board foot or an average specific gravity of .96 (very slightly less than the same volume of water). Rosewoods are considered very heavy, and are as a result, exceedingly durable and resistant to biodegrade. The density of Rosewood makes the wood difficult to work, especially in machining where planer knives and cutting surfaces are quickly dulled..
Heartcrack and Drying: Because of its weight and density, Rosewood does not expel its moisture quickly. Tension begins to develop immediately after the log has been felled resulting in fairly severe heart crack and checking, even when ends have been carefully waxed or painted. After lumber has been cut, the wood dries reasonably well especially when done slowly in a carefully monitored kiln, but a substantial percentage of degrade from checking should be anticipated.
COMMON SUBSTITUTES FOR GENUINE ROSEWOOD
Since the price of the genuine Rosewoods has moved out of the range of many buyers, many species that resemble Rosewood in color and durability have appeared on the wood market at prices which are up to half the cost of the genuine varieties. The more common of these substitutes are as follows:
BOCOTE (Cordia elaegnoides) Mexico Bocote (often referred to by its genus, Cordia) has contrasting black, green and golden yellow vibrant color with tight wild figure patterns. Commercially known as "Mexican Rosewood", Bocote is available in relatively small cuttings and the wood has a waxy texture similar to teak.
BUBINGA (Guibourtia tessmannii) Africa. Often referred to as "African Rosewood", Bubinga is purplish pink to salmon red with dark red veining. A mottled or "flamed" figure is often seen in quartersawn lumber. Bubinga is very dense with a very fine texture and since the tree is quite large, the lumber is often available in wider planks. Thicker stock is difficult to dry and prone to kiln degrade from checking. Bubinga is used to make guitars:
GRANADILLO (Platymiscium yucatanum) Mexico Reddish brown to purplish orange dependent upon the source of origin, Granadillo (not to be confused with Grenadillo or African Blackwood) is a catch all term for a number of look-a-like species that have properties relatively similar to Rosewood (specifically Cocobolo), though the grain and figure are often more bland in comparison.
MORADO (Machaerium scleroxylon) Bolivia Morado, also referred to as Santos "Rosewood, Bolivian "Rosewood", or "striped caviuna" is a close Rosewood substitute though the general color is more brown than East Indian and more purple than Brazilian Rosewood, with occasional variances of yellow, red, or black. Morado has become popular partly due to it's price, which is considerably lower than any of the true Rosewoods. It has a pleasant fragrance similar to Rosewood and a very fine texture due to a very small pore structure. As a result it can be finished without the filling and resin problems that are characteristic of true Rosewoods. The sawdust is considered a skin irritant with effects similar to to Cocobolo dust. Jacarando Pardo (Machaerium villosum) from Brazil is very close in appearance to Morado and is probably marketed interchangeably with Morado, since they are of the same genus.
PADAUK (Pterocarpus spp.) Africa, Burma, Andeman Islands Often referred to as Vermillion, Padauk varies in color according to a number of variations within species, but most varieties will display a brilliant red orange color when freshly cut, with darker crimson grain lines. Upon extended exposure to light, Padauk can gradually turn to a dark crimson to walnut shade. It is a popular wood due to its striking color. It is easy to work and is often available in reasonable widths.
The word "Jacaranda" is used regionally in South America for any wood, genuine or not, that resembles Rosewood. As a result, it causes a great deal of confusion in the wood market. Some of this confusion is purposeful, since uneducated wood buyers can often be easily fooled. The word "Granadillo" is used extensively in the Central Amarica and Mexico to market any of a variety of woods that have dark grain and are either difficult to accurately identify or have no marketable trade name. The word "Palissandre" or "Palissander" is another general term, typically overused in the European wood market, for any species of wood that "is or resembles" Rosewood. Several woods, similar in appearance, weight, and working characteristics are marketed under the general but misleading heading of "ironwood" or "Pau Ferro". Morado (Machaerium scleroxylon) is closely related and often referred to as Pau Ferro (Libidibia sclerocarpa), as are Brazilwood (Caesalpinia echinata), Maracaibo Ebony or Partridgewood (Guilandina echinata), Lignum Vitae (Guaiacum spp.), Mesquite (Prosopis juliflora), and a small gnarled shrub from the deserts of the southwestern US and Mexico referred to as Desert Ironwood. All are extremely heavy, some approaching the texture of petrified wood. Many of these woods have a dark heartwood that closely resembles the brilliant coloration of Rosewood. Ironwood is usually sought by ornamental turners and makers of jewelry and small treen.
Unless you are dealing with companies or individuals that are both knowledgeable and reputable, you should be prepared for some misinformation when buying Rosewood. It is best to educate yourself by collecting samples and reading as much as you can about different woods. Several good books about wood identification have been published, though some are out of print. One of the most comprehensive wood books available is World Woods In Color by William A. Lincoln. MacMillan Publishing Co., 866 Third Avenue, New York, N.Y. 10022 ; 1986. $39.95, hardcover; 320 pp. This book contains accurate information on more than 275 different woods from around the world. More than 200 color photographs accompany the descriptions which are well indexed. The I.W.C.S. (International Wood Collectors Society) is a wonderful non-profit organization whose members collect and trade samples of virtually every species of wood on the planet earth. For more information write to: I.W.C.S., P.O. Box 1102, Chautauqua, NY 14722 or visit their website at www.woodcollectors.org.
Rosewood is considered a rare and precious wood. It is priced according to its cost and according to its supply and demand. Prices fluxuate with political conditions (embargoes and export restrictions) and with weather conditions which affect the ability to harvest.
In the stringed musical instrument building trade, Rosewood plays a very significant role as the undisputed ideal tonewood for the back and sides of acoustic guitars. Specificly, Brazilian Rosewood is considered the best species for this purpose, but this wood is also extremely rare and inordinately expensive. It is fairly common to hear stories about Brazilian Rosewood purchases that have been made, sight unseen, wherein the wood purchased is in fact from Brazil, but it is definitely not the desired item. This confusion arises for a number of different reasons. First and foremost, there are many species of "genuine" Rosewood from Brazil, so that technically a seller can stretch the truth by representing Kingwood, Tulipwood, Jacaranda do Para, etc. (genuine Rosewoods from Brazil) as Brazilian Rosewood. Personally, I know of one such incident involving a rather large quantity of guitar wood that arrived from San Paulo, Brazil as Dalbergia nigra. It would have fooled most novices, but not those with experience. Eventually samples of this wood were sent to the Forest Products Laboratory for identification. It came back labeled "Pitomba Preta", an obscure regional name for a wood that was not even a member of the Rosewood family. One sad aspect of purchases like this one is that it is often necessary to open a letter of credit in order to buy a parcel of wood in another country. This means you pay 100% in advance, and there is little if any recourse if you are dissatisfied, or worse yet ripped off!
Imagine a wood broker who has made a poor purchase. Perhaps a species has been misrepresented to him and he has been "stuck" with a particular load of the non-genuine item. How in the world will this fellow get rid of this wood, especially if the wood was bought as genuine Rosewood at a relatively high cost. It is not uncommon for brokers to "play dumb" and allow a misrepresentation to continue. In many cases, a broker will get a phone request for a specific variety of Rosewood, East Indian for example. If the broker doesn't have any East Indian in stock, but does have Amazon Rosewood, the broker understandably might try to convince the customer that Amazon Rosewood is what he really wants! Sometimes samples are sent of the correct species, then when an actual large order is placed, an alternate species is substituted. You might be appalled at how dishonest this is, but there can be a great deal of corruption in lesser developed countries (almost as much as in highly developed nations like our own), and once the ball starts rolling it's hard to stop it.
Within the last few years, a type of picture frame has hit the shopping mall market displaying a proud and prominent gold foil label stating "Made Of Genuine Rosewood". It is most likely that these cordovan colored bright red frames are made of heavily stained Ramin or perhaps Padauk, but they are not like any Rosewood I have ever seen. I watched one afternoon at one of the malls and they were selling like hotcakes, so I'm sure the stores are happy. The customers seem happy too, believing that they have acquired real Rosewood at a bargain price. Something is very wrong with this scenario, and there doesn't seem to be any direct way of dealing with this type of mis-representation. At our place of business, we are very careful to correctly represent each species for what it is. Through the years we have developed a system that we feel is quite straight forward. If we are selling a genuine rosewood species we simply list it as (for example): Brazilian Rosewood. If however, we are selling a substitute species (that is not a member of the Dalbergia genus) we list it as (for example): Bocote (Mexican "Rosewood"). The " " are there to let the customer know that the wood it a substitute, and we try to explain this whenever we are selling a substitute species. It is very important that wood brokers and hardwood distributors maintain a sense of integrity and honor when they represent a product. If they don't, the confusion they cause will eventually backfire in the form of claims or bad reputation.
Reading this article might give the reader the impression that there are so many quirks and concerns with Rosewood that it is simply not worth dealing with all of the problems. On the contrary, I enumerate these details to introduce you to some of the fascinating differences between these and other varieties of wood, and to encourage you to proceed without fear of failure. I know that if you have never worked with Rosewood you will find it a complete and wonderful indulgence. You'll be spoiled to the extent that working with mahogany or maple might seem a little boring. Hopefully the information given here will help you navigate through and survive the Rosewood jungle.
Dick Boak is the manager of the wood division for the Martin Guitar Company. He also operates the "Church of Art" which is a renovated multi-media art studio and residence in Nazareth, PA.