Ironwood is a very rare wood which grows in certain Southwestern desert regions of the United States. With a density approximately 1.28g/cc, this unusual wood sinks in water and makes a great density lesson. Use with our Giant Pumice for a fun and thought provoking demonstration; the rock that floats with the wood that sinks! Super dense woods are naturally occurring materials. Exact density of individual samples may vary.Please note: Under a special permit from the Bureau of Land Management, a small amount of DEAD and FALLEN Ironwood has been collected by Educational Innovations... ahead of the termites. Please do not purchase Ironwood unless you are sure of its origin, as the living trees are extremely endangered and slow growing. It is illegal to collect living Ironwood in the United States.