If it is: bright orange,brown, hot gold.
has a fried/”crackled”/heavily milky appearance in parts.
Not ALWAYS damning, but pretty damning: Lots of Cacoxanite inclusions, though then you’ve basically got that… ahem… Special Super Seven Stone That Totally Doesn’t Need To Cost That Much ANYWAY. Just now it’s heat treated.
IT’S REALLY PROBABLY HEAT TREATED AMETHYST.
If it is:a more subtle, muted tone."nicotine stained"
tea stained/weak smokey quartz-ish, certified to be non-heat-treated.
Partially Amethyst one one side, partially citrine on the other.
It’s got a far better chance of being natural.
Does this change the “properties” - IMO, only a little. Genuine citrine has a much nicer feel to me than fried amethyst, BUT… it’s really more like the difference between very “milky” pieces versus very clean pieces. Real citrine tends (tends) to be much cleaner, clearer, etc… and that CAN impact the feel of a crystal over all. Not a lot, but if you’re into that thing then yeah.
(Note: Linking to that particular site is not explicitly an endorsement of that site, but honestly I couldn’t find anywhere else that had the shit side-by-side with very clear listing of “Heat treated” and “Not heat treated” so plainly spelled out.)