Hi there:
I have some dark reddish-brown/black davidite (LA) with yellow (some green) carnotite from the type locality for this mineral. Typical size of pieces: 20mm x 20mm x 18mm. Also some phurcalite with zippeite - Utah. Will have some pics available over the weekend, so if interested feel free to send me a message with your email. Will swap for anything interesting - especially fluorescent/phosphorescent samples.
Best! Mike