I buy a lot of rough on eBay, with mixed results. A few of my lemon purchases are by home grown ‘merican sellers, but returns are not usually a problem. No problems so far with international sellers, except for the long shipping time. I prefer to buy rough in person, “eyes-on”, and am blessed by living in Tucson, with ready access to the shows, but it can get dry between shows.
As far as eBay goes, know your material, and take descriptions (and pictures) with a grain of salt. Lots of synthetics are being sold as 100% natural. I even saw one a few days ago that looked like the guy took a handful of garnets, and somehow fused them together into a large block with square edges!