russ interesting vid. our basalt is different than the western material. our stuff makes rhyolite friendly. basalt, dacite and obsidian are all forms of the same volcanic material but have gone through different cooling and pressure stages . i actually have a discussion on p.p. going about obsidian being traded in new england and as usual it created a stir because somebody said there was obsidian deposits in virginia.
northeastern basalt is great for pecking and grinding though. the axes made from it were prized possessions and handed down from one generation to the next. i may still have pics of some arrow heads i knapped and then ground some where. i'll try to find em.