Four nice Montana Moss Agate slabs showing a variety of different patterning, some of which, like the fortification banding in the upper right slab and the water level type banding in the lower right slab is not seen very often in Montana agates and is reminiscent of the type of patterning you might see in a geode nodule.

These slices are from material originally collected back in the late 80's. There are a few fractures as can be seen in the photos. Fractures are fairly common with Montana agate nodules.

Going clockwise from the upper right, the approximate thickness of the slabs are 4, 4.3, 5.3, and 4.8 mm thick.
Photographed wet to show details and dry to show the slab dimensions(second photo).  The dry photo is on a 10mm or 1cm to the square scale.