Lab rubies, sapphires, emeralds and basically anything you can think of with a known chemical makeup is being produced en masse by factories all over India and China.

Here’s just one sellers assortment of various “roughs” https://www.gemsngems.com/product-category/rough-stones/lab-...

As someone who doesn’t care about the authenticity of the gems provenance and only about having consistent physical properties for rock tumbling and gem faceting, it’s been very nice for the budget