Mixite is a rare bismuth copper arsenate, and from Laurium is not in itself rare... but it is often found only as sparse microcrystalline material on large plates, and seldom as concentrated crystal clusters like you see here. This attractive turquoise-colored cluster of mixite crystals is nearly 2 cm, and winds attractively down the matrix. Unusually rich for this locality, but also for mixite from any other place as well.