More than likely it is dyed howlite. I agree that the stringing looks more like someone took a temporary string of beads and added a clasp, rather than doing a good job knotting and adding spacers between the beads. Real turquoise beads are very uncommon these days (and even if real turquoise, it is almost always either reconstituted - i.e., mostly resin/plastic, stabilized and/or color-enhanced). You could try flashing light down one of the drilled holes to see if the color goes all the way through. There are other tests you can perform, some of which would require sacrificing a bead, which you likely don't want to do.
I would think it would be valued more as raw material for someone who does beadwork. The "325" isn't a metal fineness of which I'm aware (could be a "925" sterling mark that didn't get fully stamped, though even that doesn't guarantee it is sterling these days).
Here's a photo of what looks to me like 325. I suppose it could be 925 but it's an odd shape if so.
