If we're replicating the filming model, clear domes, sprayed with this
Krylon K09053000 Sea Glass Spray Paint, Amber, 12 Ounce - - Amazon.com
www.amazon.com
As that's how it's current iteration in the smithsonian was done.
I've heard (unconfirmed as far as I know) rumors that the original domes were clear, sanded for a frosted effect, and sprayed with something like this
(I seem to recall Pelikan brand but can't find any at the moment)
Amazon.com : Thornton's Luxury Goods Fountain Pen Ink Bottle, 30ml (Orange) : Office Products
www.amazon.com