When you order gemstones online, how do you know they are real and colour correct?

[jennifer_bloom]

I want a citron and a rose quartz and an amethyst but I saw online that some of the colours came out darker then desired and there is also speculation some of the stones are fake or glued on.

[Fireguy17]

Unless you have the correct testing equipment you can't be sure.
If you send them out to get tested that will cost more than the stones cost.
Best suggestio is to go to a jewelry store, not a chain store, a small mom and pop store and they should be happy to get you what you want.
On the plus side those stones will not be too expensive since they are on the lower end of the semi precious price scale, unless you want a really big one.
Just for grins look at an Amitrine stone, half amethyst, half citrine in the same stone, kind of a freak of nature.
I always liked them, something different.
Those are usually emerald cut, or more rectangle shape to show them off better.
I'm a retired jeweler/store owner.

[NamerOfStars]

Unless you have specialized equipment or are running very specific tests (hello, Archimedes- Hey! You forgot your toga! Archi- well, THAT will make for interesting headlines tomorrow; I wonder what he found out?), I don't think you can.

Unless it's Alexandrite, or the other stone (zultanite, I think?) that does the same thing; that you could check with different light sources.