You may possibly have purchased a lead-filled sapphire. These are being offered more and more. If so, basically, my understanding is these are deeply flawed garbage quality natural rubies and sapphires that have been cooked to such high temperatures that the inclusions burn up and then the holes or gaps are filled with lead glass, which greatly enhances clarity and color as well. Sometimes they are cooked to such an extent that several stones fuse together. They look very pretty and most of the rubies you see at Macy’s and many other jewelry stores are actually lead filled, thus worth only pennies on the dollar at most compared to a natural ruby or sapphire. However, funny things do occasionally happen on eBay so I don’t know that I’d go around chopping it up without first testing it to make sure it isn’t something good. I have personally received tons of junk on eBay but a couple of times I did get huge bargains from people who didn’t label what they had correctly. Under a 10x loupe you should be able to see gas bubbles if it’s a lead filled sapphire. If not, or if you instead can see natural flaws in the stone,, consider other tests.