It is a variegated form of Selaginella kraussiana. It is often sold under the name 'Frosty fern', though it isn't really a fern. Selaginellas are often called spike-mosses but they aren't really mosses either. Club mosses are probably their closest relatives.

If you can salvage some healthy branches they will usually root easily in a terrarium or some other container where high humidity can be maintained. Moderate light is best. I would recommend pouring boiling water over the soil you use prior to planting to prevent mold (let it cool first of course).

"If you can salvage some healthy branches they will usually root easily in a terrarium or some other container where high humidity can be maintained."

Great! Thanks for the info. My frosty fern leaves are pretty much dead. Did you mean live branches?

By live branches I mean ones that appear to have reasonably healthy leaves on them. Depends on how far gone it is.