Found this interesting article on Rosewood for guitars

Chris Herrod (sales manager from Luthier Mechantile International) For many years the crème de la crème of back and side woods was Brazilian rosewood. Though this wood is still in common usage, it has been protected against import and export by the CITES [Convention on International Trade in Endangered Species of Wild Fauna and Flora] treaty since 1991. For this reason, a number of alternatives have surfaced- one being Indian rosewood, which in turn has become a standard choice and should now be considered a traditional tonewood itself. It was during the 60's that most large manufacturers switched from using Brazilian to Indian rosewood.

Brazilian rosewood is sought after for its (usually) dark brown color that ranges from chocolate brown, to rust or a warm burnt orange. Finer examples feature fine black line figuring and spider webbing (where the black lines make web-like shapes that cross from one annular ring to another). The tone, some say, is incomparable, though it is often argued that this opinion is once again, a habit of tradition. Great projection, with strong, balanced bass and highs are its trademarks.

Indian rosewood varies quite a bit in appearance from Brazilian rosewood, though it is still quite dark. Basically brown, but with purple, gray and sometimes red highlights, it is known for straighter, more homogenous grain lines and a lack of ink-line figuring. Some say it is on par with Brazilian rosewood for tone (a few say it is superior), and though it is far easier to procure and less expensive, it is nonetheless considered the mark of a higher-end instrument, especially by manufacturers. Some say it lacks a bit of the projection that Brazilian rosewood is known for, but this is debatable.

Other rosewoods are found in Asia, Africa and South/Central America, offering a tremendous variety of choices for those who like the rosewood sound. The most exotic of these is African blackwood. Strikingly different from other rosewoods in that it is flat black in color, and among the densest woods found on the planet, it is also one of the most expensive. The trees grow in isolated areas of the West African deserts and the trunks of these trees are twisted and small, yielding little guitar-sized wood. For those daring luthiers who don't mind dulling their chisels on this hardest of guitar woods, African blackwood can contribute to a rare and valuable guitar with outstanding volume and power, given that the top is voiced appropriately.

There are other rosewoods that compare in density to Brazilian rosewood, such as Honduran rosewood and Amazon rosewood. Honduran is more of a brick red/brown in color and Amazon is similar in color to Brazilian but is usually found with less figure. Both of these woods feature tight grain lines and both have adherents that claim they are finest tonewoods available.

On the wild side are: Southeast Asian rosewood, palo escrito and cocobolo rosewood. Southeast Asian rosewood is very hard to come by and was only available from Luthiers Mercantile for a 4-year period during which we exhausted the stock from a single shipment. There may still be many good logs left but at this time, no one is harvesting them for instrument use. The wood was very dramatic in appearance, with brick reds, magentas and purples combining in unique ways. Many sets also featured dramatic black line figure and attractive sapwood centers.

Cocobolo, on the other hand, is readily available from Mexico; this superb tonewood has bold, distinctive orange highlights with plenty of black lines that can often show exciting swirly patterns. Some sets are dark reddish-brown. Cocobolo is among the heaviest of the rosewoods and is known to impart a strong bass to guitars. Many luthiers shy away from using cocobolo because they have an allergic reaction to it when sanding and, because there are abundant oils in the wood, it can be difficult to glue.

For those who can work around these problems, cocobolo is a great favorite for both tone and beauty.

Palo escrito is a tan wood with reddish-brown lines that create unusual patterns in some sets, much like colobolo. This is a lighter-weight type of rosewood. Guitars with back and sides made of palo escrito are known for a sweet high end and good punch. This wood is becoming a popular choice for flamenco guitars, but steel-string builders who are experimenting with it, most notably James Goodall of Goodall guitars, are getting excellent results with it.

Finally, from the rosewood category, there is Madagascar rosewood. Little can be said about it that hasn't already been said about Brazilian rosewood! Visually, it is a dead-ringer for Brazilian, though in general it is more red or rust colored. The main differences are that Madagascar rosewood is not illegal to import, it is far less expensive, and a little lighter in weight. More than a few builders claim that the lower weight bestows an additional sonic liveliness that surpasses Brazilian rosewood -and indeed, most other tonewoods. The tap tone of this wood has a noticeably strong, sustaining quality.

There are a number of other woods that, because of their higher density, help create a rosewood-like sounding guitar, but do not come from the rosewood family. Visually, none of them would be mistaken for rosewood, but they are all quite attractive in their own right. On the higher-end are Macassar ebony and ziricote. Breedlove Guitars, a company that has created models from numerous alternative tonewoods, is very fond of both of these woods. Macassar ebony, as you might guess, is a black wood but with dramatic blond streaking which creates a beautiful liquid or marbled appearance. Ziricote is grayish in color and features intense spider-web figuring and layered effects.

Both woods are brittle and hard to work with. Both are expensive but their high density allows for great tonal balance and volume and the scarcity of well-figured sets adds value to the instruments. The remaining rosewood alternatives, on the other hand, are relatively inexpensive and easy to come by. From Africa there's bubinga, which has a nice reddish-mauve brown color and often sports an interesting 'bees-wing' figure that gives a nice three-dimensional shimmer to wood under finish. Also from Africa is padauk. A brilliant purple-red wood, it oxidizes to dark brown over time. Finally, there is wenge a very dark brown wood (verging on black) that some well-known builders, such as Mark Blanchard, have had good results with.

From South America there is grenadillo. This wood has a nice purple brown color reminiscent of Indian rosewood, except that it does not have the straight lines that Indian has. Grenadillo does have a subtle wavy figure, a bright responsive tap tone, and attractive sapwood centers are commonplace. It is popular in Brazil, but it is relatively new to American lutherie. It promises to become a favorite among steel-string builders. Pau ferro (or morado) is well known as a fingerboard wood on electric guitars and basses and is coming into its own as a back and side wood. It is much like Indian rosewood with dark, straight, vertical lines except that gold, beige and brown substitute for the dark browns, grays and purples found in Indian rosewood.