Dunno - we've got three different kinds of Locust on our farm. If you can season them indoors (and keep bugs outta them), then the wood is "rock hard" like you said. On the other hand, if bugs get to them, they're dust in a short time. Bugs don't bother them while the tree is still in the air, but cut it and away they go! Don't think it's the difference in Locust that makes it different, it's probably a difference in bugs! Some reason, they love the stuff! Lot of people use Black Locust for firewood. Neighbor cuts it up all year to sell . His "buyer" sets it out front of convenience stores in Omaha & Lincoln. Gets $4 for 6 little pieces. Neighbor makes $10,000+ profit a year, by just "piddlin". What ever works, I guess!