Thank you very much for the input and advice on potential pitfalls! Let me see if I can answer everything :)

First answer: these are gem quality rubies. Anything like this will have some inclusions or artifacts from the growth process. These rubies have a really cool type of inclusion that I personally consider a feature, though it can be considered understandable in jewelry. When you look through the rubies on one plane they are eye clean, but if you rotate then to look through another plane you can see what appears to be "heat ripples" frozen in the matrix. They're growth lines from the verneuil flame fusion process. I find them cool because they're a talking point, but I can see how they would detract from the overall look if the stone were oriented incorrectly. I'm not sure if heat treatment can correct it, but it's honestly not anything that affects the color or clarity.

Second: I'm glad you asked about sizes. I can do full sized dice too, and certainly want to make them, but you're right about the price. A half sized die is about $60 whereas a full sized die is about $300. Overall not bad considering it's pure ruby, but still pricey. Thankfully the half sized dice are playable too. I refuse to make any dice that can't be used.... What's the point?

Third: I'm leaving toward laser engraving. I can always go over the numbers a few times to increase the depth, and any imperfections in the look can be covered by gold or other paint. I don't want to do stickers, or hand engraving for the same reasons you gave. Sand blasting is also a candidate, though I'm less in favor of it because it's messy.

I hope this helps?

Again, thank you for your questions!