Hand-carved arrowheads and jagged spears made of obsidian, a sharp rock formed by volcanic magma, are remnants of vast prehistoric trade networks that once cut across western North America.

On April 21, the Sarasota City Commission is set to vote on a citizen appeal of The Obsidian, a 14-unit condominium project that, as proposed, would stand as the tallest building in downtown at 18 ...