I always liked emeralds and tanzanite.
For luster and glow I think opal and moonstone beat pearls, at least for my taste.

...I always wanted a little leather bag full of precious gemstones to pay for stuff. Like a pirate. Or the Goonies.

Haha, that would feel rather good, an adventurous pirate. And more impressive to have precious gemstones for trade than diamonds. You can have millions worth of diamonds and barely have a handful.
Just don't put tanzanite in it. I found out the hard way it is rather brittle :/ Maybe the tumbled version does better but still...
Rubies would be nice

You'd have to wait and see how your object of affection would react

Ouch...

She can shove a pearl or 2 through there right?

Of course.
At the expense of breathing.