Sisterly Creations design and create unique and beautiful Montana Moss Agate jewelry and Montana petrified wood jewelry. Montana Moss Agate, born from the fiery depths of the earth, then hidden in the remote wilds of Montana, thousands of years in the making and now â discovered and expertly crafted by Sisterly Creations! Each piece is âone-of-a kindâ, designed by nature, and beautiful to behold. Sisterly Creations is the product of a lifelong love of rock-hounding and jewelry crafting. Montana Moss Agate Jewelry is brought to life by these two native Montana sisters.