Is my blue topaz actually dyed quartz?

I saw someone on r/mineralgore who got sold blue topaz that was straight up dyed glass. Mine doesn’t have any dye come off when wet like theirs, and the color and such generally seems fine to me. And it’s definitely natural minerals and not glass. But there are some tiny “pits” of color in the stone (flecks of vibrant blue) which got me wondering if it’s cracks where dye settled. And I thought low grade topaz was fairly cheap, but then I saw claims that it’s expensive even if it’s not jewelry grade? It’s pretty either way, I’d just like to know. The internet has me questioning everything haha.