I believe it’s from Myanmar. I know the shape, it’s an ancient cut, which can’t help much with origin, since it’s a globally ubiquitous motif, but it’s a really great stone, and the color may be what was once known ‘"pigeon blood’ red, and very prized. If not from Myanmar, it is possibly from Sri Lanka, but those tend to be more pink than red and include more fractures. But thats another possible origin. My last guess would be Mozambique, again based on color, but not a modern stone, it is ancient, that much I am sure of.
It’s cut, it’s not a natural shape.