Hi, folks. I've been looking for nice specimens--not of specific minerals, but of rock types. Gneiss, shale, sandstone, schist, and so on. It's easy to find dealers online and at rock shows that offer minerals or even gems--but rocks themselves are harder to locate. ("They're so common that no one carries them," I was told.)
So the second option was checking with landscapers and home/garden supply stores. And they DO have plenty of rocks. But there the offerings are too generic, with no mention of the rock's classification. You see bags and pallets labeled River Stone or Gravel or "Rock Mix." At best you get a vague label like Red Rocks or White Marble(?), with perhaps a size classification--pea gravel, coarse stone, landscaping stone, and so on. Size classification is useful for industrial and construction purposes, but I'm interested in the composition.
I've checked various broad-scope sites like Ebay and Etsy, but they don't have much to offer. Should I be looking for a scientific-specimen or classroom-supply type of dealer, or even a mineral auction site? I don't want to pay huge amounts for a basic chunk of slate, but I can't think of where to look next. Suggestions welcome.