i always assumed her cutie mark was “finding the beauty within” or something like that since she can see beyond what is right in front of you to find/make something that really shines. like how she found those first gems in the stone.

THE SUN
 
IS THE YELLOW ONE

@Background Pony Number 17 
I’m ok with this.

What Rarity considers “rare” and what Maud considers “rare” are two different things: 

THE SUN IS THE YELLOW ONE

First off swev if you compare the episode where she was forcing Maud 
on ponies to where Pinkie was worried that Starlight Glimmer an her sister 
looked and seemed from her perception that they weren’t going to be friends 
after all Pinkie has the right to be apprehensive considering the last time 
with her five friends admitting that they just didn’t feel anything towards 
her. not to mention this was a different situation since she underestimated 
her own sister an Rarity never said and or gave a hint she was a professional  
rare gem finder she probably doe’s know some gems that are rare but alot an quite 
a few and most of the time she assumes they are rare so what you drawn has no merit.

@TheBrianJ 
Just because it’s a gag doesn’t really make it much excusable if it’s at the expense of established traits of a character. Take for example how often Pinkie gets hurt as a character because of numerous “gags” that hurt how she appears for the sake of “lolrandom”.

@TheBrianJ 
When gags are bad, they tend to get called out.

This seems like an awful lot of drama and over-reacting to what ammounted to a 5-second gag.

Can we please just point out that regardless of how you feel about her knowledge of rarity of gems (which you’d think she’d be an expert in) she has been shown before to use a gem finding spell to locate gems hidden in rock. Even if it wasn’t rare like she thought it was, she could have at least used that to locate what was available in the cave for her?
 
I really, really don’t like Maud. She comes off as a waifu bait material character like “Wow look how cool she is haha she’s so stern it’s funny” and it just gets annoying. I don’t find her to be a good character, she just turns everyone around her into a joke for that idea of “haha look how awkward she makes people feel”.

@MadVillan 
Aye. They needed a reason to have Maud antagonise Rarity so Starlight could step in as the superior friend.

@hakirayleigh
 
Remember how in Secret of my Excess Rarity is able to instantly appraise Spike’s fire ruby?

@Starswirl 
I remember she said blue sapphires are rare, but she’s talking about her chances to find it, not its Geodiversity.

@hakirayleigh 
On the contrary. Rarity knows what gems are rare and what aren’t. Or at least she used to before this episode.

@Background Pony #6444 
Ok. +10 by your effort.

@hakirayleigh 
Rarity puts rocks on frocks, and looks cute in socks.
 
I could have gone for the other obvious rhyme but I don’t want to go there on an image marked “safe.”

Man, she needs to hone in her dousing techniques

Rarity skills is only find gems to combine with her frocks. Not looking for extremely rare ones.

Depressingly accurate.

I recall hearing this kind of joke from another fan years ago and didn’t cotton to it much then either.
 
While an obnoxious number of axillary talents can get boring quick(see Fluttershy in fan works), I like it when they make sense. Even if you explain it away as Rarity only focusing on gems’ aesthetics rather than their geological attributes, you’d think she would have hunted for them enough to know what’s rare and what’s common.