Zollernia spp. of the family Fabaceae (syn. Leguminosae) the legume, pea, or bean family. There are at least 8 species in the genus Zollernia that use the name pau santo as all or part of one or more of their common names and I do not know which are represented on this page. ALSO, there are at least another 7 totally unrelated species, all from different genera, that use the name pau santo and any of them could well be represented on this page. The joys of common names in wood.
Zollernia paraensis, which I think might be some of the woods below, is a South American wood, also known as Brazilian blackheart (among many other common names), which is dense, heavy, and moderately easy to work.
my samples: NOTE: these pics were all taken in very bright incandescent lighting ("soft white" at 2700K) colors will vary under other lighting conditions
First, these are not actually MY samples, they are pics submitted by Kelly Peterson who reports that the snakeskin figure is NOT representative of the species, although the color is correct. Further, he states that the pic on the right shows a resawn plank with the piece on the left showing the fresh cut color and the piece on the right showing the same but moistened for the pic. Kelly reports the species as hard and heavy and he says (and this is collaborated by other sources) that resins cause the wood to darken over time to a dark greenish gray, nearly black (particularly as seen from a distance) as shown in the first pic. His report on the weight of the wood, at over 80 pounds per cubic foot, is considerably higher than other sources, BUT ... he's actually weighed the stuff and I can't say that for sure about any of the other sources.
two more pics from Kelly ... the first is of a more "normal" plank without the snakeskin pattern and the second is an edge view showing face grain on top, edge grain on the bottom and some sapwood at the edge in the middle of the pic. My thanks to Kelly for his contribution of these pics and information about this wood.
plank with color that is probably quite accurate
planks with color that might be accurate (the one on the left would be fresh cut and the one on the rigtht would be aged, but even at that, the sapwood is likely not that bright)
three planks, the color of which is unlikely. These are from an unreliable source.
bowl by Steve Earis and the blank from which it was turned