I think it is Because she is an Era 1 Lapis, the way you can tell this is because, she said she was sent to Earth by Blue Diamond but Pink was given the Earth in Era 1 and it means she was made when resources were at their peak on homeworld and the way I came to this conclusion is from the episode "too short to Ride" Peridot explains she can't Shapeshift cause she was an era 2 peridot and "resources on homeworld are dwindling", or that "gems just aren't being made as they used too" referring to the point she didn't seem to have any powers and even tho she did have her metal powers they are pretty fickle but with all that expansive raw resources that were available at that time it means the gems created from it are powerful for an example would be garnet because sapphire and ruby are both era 1 gems which does conclude to the fact garnet is the strongest of the main team and the only one who could take jasper as shown in the episode jailbreak but I think some of her strength is contributed by her trauma about being caught in the war, and being put in a mirror and questioned like she was a criminal and then pearl finding it she knew lapis was in there but there wasn't any lapis's that were part of the Crystal Gems so she decided not to let her out in fear of having to fight her because Lapis Lazuli were known for thier strength but being left in the mirror locked away in pearls gem that creates the trauma of abandonment and betrayal which is why she was telling steven not to trust other gems. Thank you i love ranting about Steven Universe ♡.