What color is it? Sounds like maybe burlap if it has a weave pattern. Remember that with micarta, you are actually getting two types of dust, dust from the resin and dust from whatever the layers are made of (linen, paper, burlap, carbon fiber, etc.), as well as possible fumes from the resin as it heats up. Carbon fiber will make you itch like crazy and some others may as well, not sure because I haven't used it much, but it wouldn't hurt to cover as much skin as possible. If you go slow cutting and shaping so that it doesn't get hot, it'll mainly be dust and a dust mask would probably be sufficient. If shaping on a belt grinder, you might want to get a respirator to help with the fumes. You can get one for around $20 at a home improvement store so I'd recommend it just to be safe. Also, if you do most of your shaping before attaching the scales to the blade, you can keep the micarta wet to help keep the dust down. Soapy water works better than plain water.