I have to admit, the statements at the beginning of the clip had me skeptical, so I was pretty amazed by the quality of the tones produced by whacking these boulders.
On the other hand, lots of rocks produce tones when whacked. The degree of weathering of surface material in the PNW ranges from fresh to utterly rotten, and I've found that the "ting!" to "thunk" quality tells me quite a bit about the degree of freshness. There's an outcrop of some basalt-like flow with platy jointing along the road where route 140 climbs up the east side of SE Oregon's Guano Valley, near the Nevada border; the resulting flat rocks produce nice chimes too. A common sight at Oregon craft fairs is wind chimes made from obsidian "pencils." I've been to several caves where "organs" made either by speleothems, or columns of limestone left behind as falling water dissolves the rock between them, are played. And an uncommon rock type called phonolite gets its name because, yeah you guessed it. "The name phonolite comes from the Greek meaning (more or less) "sounding stone" because of the metallic sound it produces if an unfractured plate is hit, hence the English name clinckstone."
In short, if you didn't realize that rocks can produce some very interesting- even pleasing- sounds when struck, they do. In my experience, being familiar with those sounds doesn't tell you a lot about the rocks, but neither do they tell you nothing. Of course, it helps to have hit a lot of different rock types, many, many times.