Drusy, druzy, druse. These are all different spellings for the same phenomenon: tiny quartz crystals that formed within or on the surface of other stones.
How it's formed: When ground water carrying dissolved silica is forced into a porous area of a rock, rapid cooling often occurs, causing the formation of tiny crystals on the surfaces or in cavities of the rock. The clear crystals often form on top of previously deposited minerals.
What it means to me as a jewelry-maker: I love the texture. It's like a dusting of sugar. I tend to purchase druzy nuggets, big and luscious, and use them as focal points for my pieces. I just picked up some druzy agate in shades of orange.
Look for some pieces soon.