Montana agate nodules in the rough are available in large sizes. (Stock 536) These are complete nodules usually containing black inclusions or manganese dendrites or moss, in a milky to blue/gray translucent chalcedony. Sizes for the Montana agate nodules, good grade and complete agate nodules are from 1-3 lbs. The unique patterns of Montana agate are well known for beautiful one of a kind jewelry. There may be fractures, but orient your template for the best cabochon patterns.