The shop you enter is dimly lit, and there seems to be no sensible organization to the piles of rocks, minerals, crystals and sparkling gems on display. The shopkeeper in the back looks up from their book, smiles, and gestures to the sign before looking back down at the page. In clear lettering, you read: 

I have a piles of gems and rocks from exploring the Mines and no plans to use them, so come grab a bargain! Come to the counter when you're ready to pay.

$3000 per gem, or $2500 each for purchases of 3 or more

Also currently accepting offers of Labradorite in a 1:1 trade for other gems 

On sorting through the piles on the shelves, you find the current inventory:

Amethyst x 4

Apatite x 7

Blue Sapphire x 8

Citrine x 8

Emerald x 3

Garnet x 1

Onyx x 5

Quartz x 7

Rose Quartz x 2

Ruby x 6

The shopkeeper closes their book and looks around at the store, a lot emptier than it was before. They shrug and pick up their pickaxe, ready to go find more stock.