“Well, that story didn’t make much sense,” Scootaloo muttered, “Why would Princess Celestia specifically send a letter to her dad saying his daughter was a nice filly? Especially if they’d never met.”
“Yeah. I kinda think she was makin’ it up.” Applebloom agreed. “Pity. It’d be nice to know how she really got her cutie mark.”
“Aha!”
The others turned to Sweetie. “What is it?”
“Well, it looks like most of the diamonds in her tiara are brilliant-cut. That means they’re the best kind of cut for a generic diamond. I can’t see any princess-cut gems, but this is the important one.” Sweetie pointed to the stone right at the middle of the cutie mark tiara. “That’s a well polished but uncut stone.”
The others stared at her as though she’d grown a second head.
“What? I helped Rarity for a couple of Loops.” Sweetie blushed. “Anyway. That means she might actually be – literally – a diamond in the rough. She’s just never had the chance – never faced the stress – that would let her shine.”
Scootaloo rasied a hoof. “By stress, we’re talkin’, like, an alien invasion, right?”
“Probably,” Sweetie giggled. “But it does mean something. She’s been too spoiled to develop her full potential.”
https://www.fimfiction.net/story/98568/10/mlp-time-loops/loops-10