Olivenite

A flat plate of iron-stained vein Quartz has a rich coating of deep bottle-green Olivenite crystals to about 6 mm long and covering an area of approximately 3.5 x 4.0 cm. From Wheal Unity, part of the St. Day United mines sett in the parish of Gwennap, Cornwall, the Olivenite forms broad lath-like, somewhat spear-shaped crystals.  Please note that an elongated area of these crystals is damaged due to contact with the adjacent rock while in-situ; this manifest as pale green crystals with a dull lustre and sheared break.