Im into gem cutting as a hobby so its been great for me to find stuff like these cheap ruby roughs[1] but yea, its gonna fuck up anyone selling the natural stuff.
[1]https://www.etsy.com/listing/4443524661/lab-grown-red-ruby-s...
Not ridiculously cheap, but probably within the realm of most people on this forums budget if they want to get into it.
Another plus side of the lab grown gems is that they are usually uniform in quality. Natural stones can have a lot of variance in hardness and cracks that make them need a more nuanced hand on.
If anyone running across this comment thread gets interested, the material you are looking for is "lab grown ${gemstone you care about} rough"