Beautiful Montana Agate found in the alluvial gavels of the Yellowstone River and its tributaries. These natural Montana Agate stones measure 31 x 16mm each and are top drilled. Though not identical, these two Agate stones are similar enough to be used as a pair. Agate gemstones enhance creativity and strengthen the intellect, making them a beneficial stone for both students and artists. Agate is also known as a good luck gemstone, and a stone of harmony. Agate beads balance yin/yang energy.