Think of the structure of wood as being a series of tubes all bundled together. Looking at the wood from the end grain, stabilized wood has the tubes filled with a man made resin of some variety. Many exotic tropical woods have natural resins and silicon compounds with perform the same function. Most unstabilized woods have open ends to these tubes.
To determine if a wood is stabilized, look at the end grain. If no pores (tube ends) are visible, the wood is probably stabilized. If you observe most of the tubes filled, but observe a few open tubes the wood is most likely a highly resinous wood. Both stabilized woods and resinous woods are quite dense. Another test is to wipe water across the end of a smooth cut section of the wood, then wipe across the same area to clear any surface moisture. If it still looks wet it probably isn't stabalized. If you want to tell the difference between stabalized wood and exotic wood, take a rag with denatured alcohol on it and rub a spot on the wood four or five times and see if some of the color of the wood comes off on the rag. If it does, it is most likely not stabalized. Of course there are different ways of stabalizing and results will vary. The commercial guys use an acrylic resin which is very durable.
Jim A.