Guaiacum spp. of the family Zygophyllaceae. The wood is primarily from Guaiacum officinale and Guaiacum sanctum, but may also be from Guaiacum coulteri, Guaiacum angustifolium, and Guaiacum guatemalense. Native to several areas in South America
The name means "tree of life" which was given for its medicinal properties.
Other common names include palo santo, greenheart, ironwood, and verawood, but ALL of these names are also used by several other, unrelated, species. True verawood (as opposed to Guaiacum spp. CALLED verawood) is a very similar wood from the same family (but a different genus) and is often confused with lignum vitae.
This wood is one of the world's most dense and will readily sink in water. It is quite hard and takes a high natural gloss. Because of a pervasive oily substance in the wood that reportedly does not dry out over VERY long periods of time, it has been widely for support bearings for propeller shafts in boats (including submarines) and, likewise, support bearings for power generator shafts.
In woodworking, it is widely used as a mallet wood because of its weight, strength, and durability. It is fairly readily available, but expensive.
NOTE: I have seen some claims, which I cannot substantiate but feel might be true, that a fair amount of the wood sold in the USA these days as lignum vitae is actually verawood / Argentine lignum vitae, both of which are in the genus Bulnesia and are not related to lignum vitae (but they DO have somewhat similar characteristics and can sometimes be difficult to distinguish from lignum vitae
both sides of a sample plank of lignum vitae / Guaiacum officianale --- HUGE enlargements are present. This sample was loaned to me by David Clark whom I thank for this and other contributions to the site. NOTES: (1) the sample is labeled with the common name "guayacan" but since that name is used as all or part of one or more of the common names of at least 70 different species, I consider it utterly useless as a designation. (2) the labeled side is raw but the 2nd side has been lightly sanded to 240 grit and shows a slightly redder tinge. The end grain update below as been sanded even more and shows a strong change from red to green. Over time it will revert to green.
end grain and end grain closeup of the piece directly above
END GRAIN UPDATE from directly above. See comments on color with the face pics above
a set of small cutoffs. The first pic shows the unsanded side of each and the second pic shows each piece after I sanded it down to 100-grit. The piece in the lower left is cut from one of the pieces that looked exactly like the top piece, but this is a side grain (flat cut) and freshly cut and sanded. The other edges that are sanded were not fresh-cut prior to sanding so still retain much of the patina.
the two lower pieces from the set above, but this time face-on and up close. The one on the left is a flat cut face freshly cut and sanded and the one on the right is a butt-end face freshly sanded but not freshly cut. As I was rough sanding the butt-end face, there was a fairly bright green dust and the piece was more green than it became as I sanded it down with a 100-grit belt.
side grain closeups of the same pices. The one on the left shows a closeup of the top edge of the one that is show face-on directly above and the one on the right shows a side grain face of the one that is show butt-end-on directly above.
end grain closeups of the same pieces. The one on the left is the end grain of the piece that is shown face-on in the first set of pics and the one on the right is the end grain (the same butt-on view) of the one that is shown butt-on in the first set of pics.