A fantastic rarity from the old era of mining at this important locality known for its rare copper mineralization. This piece features THICK veins of krohnkite (kroenkite) completely filling a fissure seam in matrix, and 360 degrees around. In the middle is a narrow vein of natrochalcite! These are seldom seen for sale anymore and can be anywhere from 50-100 years old. This is a very rich, beautiful specimen.