High Quality Rubies were previously sourced from Burma. Supplies are harder to get and they are sourcing them from deep mines.
Another major and perhaps the most significant problem are ethical issues associated with the supply of Ruby from Myanmar. The large jewellry brands are keeping clear.
https://www.ajsgem.com/articles/ban-burma-ruby-and-jade-latest-news.html
Rubies are being sourced from deep mines
For my latest summary on mustang and why it’s such a great investment
https://hotcopper.com.au/threads/go-long-on-mustang.3747201/#.Wd6UBLbZWaM