Donuel, you want Mexican Opal in the matrix. It's commonly available at a lot of rock shops, and any gem show, besides online sources. I cut a bunch of it trying to make a set of earings for my Mother that matched an opal pendant I'd given her. I've got some at my elbow.

Opal is deposited in cavities in vocanic rock by superheated water, and the mexican localities are that soft red you refer to. The bad news from a jewelers viewpoint, is its softness and tendancy to crack. You won't have any trouble finding some though.

Jeff Smith