How do collectors evaluate gemstones?

Collectors end up judging gemstones with that old “Four Cs” thing, colour, clarity, cut, carat weight, but they also dump a big premium on whether the stone is unheated or not treated, plus where it came from and even the past record, like historical provenance.

For real connoisseurs, the depth of colour and that clean hue purity come first, and right after that is the lack of artificial augmentations. Having a certification for the source from a legendary place, like a Kashmir sapphire or a Burmese ruby that is strictly unheated, can multiply the stone’s market worth in an almost exponential way, even if other stones look physically similar but come from different areas.