Nuts with the skin on are generally-referred to as natural or unblanched. Those with the skins removed are referred to as blanched or skinless. Almonds, pistachios and hazelnuts are available both natural and blanched. Pecans and walnuts are not blanched but the skins are so thin that they don’t need to be removed.
Store nuts in a plastic bag in the freezer. If you need to grind nuts in a food processor, bring them to room temperature before grinding. Cold nuts will clump up and never grind finely enough. Warm ones will turn almost immediately to nut butter.