This lot has caused controversy on tik tok because consensus is so divided. Some believe this is heat treated amethyst. Others believe that this stone is real citrine.
The yellow is consistent with iron staining. However, iron staining doesn't happen in sporadic patches inside the crystal like this. More likely this is heat treated quartz, not amethyst, which would be darker in colour.
Anyway. Citrine is incredibly rare. Although we don't think it's real, it is still pretty quartz. We do know citrine is a popularity stone and correlates to the solar plexus in crystal healing.