Now that I've found some gems, how do I convert them to cash?

Hint 1 of 12:

Hunter, the manager of the Casino, offered to server as your broker for
anything you might find.

Hint 2 of 12:

You should have taken him up on it.

Hint 3 of 12:

Once you have, all you have to do is to get your ore samples to him.

Hint 4 of 12:

He's not around the bar very much.

Hint 5 of 12:

But this is high-tech; surely there must be another way to get the samples to
him.

Hint 6 of 12:

I don't suppose you can fax them...

Hint 7 of 12:

Although there IS a "special" telephone in the Center Pit Staging Area that
seems to have some additional capabilities that the other telephones
throughout the game do not have.

Hint 8 of 12:

Find the telephone near the top left corner of the map of the Center Pit
Staging Area.

Hint 9 of 12:

Notice the ability to introduce objects into the telephone.

Hint 10 of 12:

These objects are transferred to whomever you call.

Hint 11 of 12:

Place your ore samples in the bin of the telephone, and "phone" them to
Hunter.