Andradite Garnet
Posted by: Raymond McDougall on 11.23.2022 | Filed under:

Andradite Garnet

Specimen # 201153
Mineral: Andradite Garnet
Location: Cornwall Iron Mine, Cornwall, Lebanon Co., Pennsylvania, USA
Size: 3.6 x 2.8 x 2.8 cm


Detailed Description

This is a remarkable Jeykll and Hyde andradite crystal – I’ve never seen one like it. It is comprised of dodecahedral and trapezohedral crystal forms. However, viewed from one side, it appears to be essentially a dodecahedron (with minor modifications), and from the other side it is a trapezohedron with almost no sign of dodecahedron at all. (!) Looking at these photos, it’s hard to believe the dodec and the trapezohedron are the same crystal, but that is indeed the case. The first five photos show a rotation counter-clockwise, with the second and fifth showing the Jekyll-Hyde appearance (in photo 2, the dodec is on the right, and in photo 5 it’s on the left). In excellent condition, no damage. From the John S. White Pennsylvania Collection, this is an awesome specimen from the Cornwall Mine.

About John S. White

About the Cornwall Iron Mine

The Cornwall Iron Mine began in 1732 and, after operating continuously for over 230 years, it is regarded as one of the great historic mines of the American Northeast. Iron from Cornwall supplied efforts in the Revolutionary War and, over the history of the mine, more than 106 million tons of iron ore were produced. The Cornwall Iron Mine complex also produced gold, silver, copper and cobalt during the life of the mine. In 1972, Tropical Storm (originally Hurricane) Agnes caused the remaining mining operations to flood beyond commercial recovery, and the Cornwall Iron Mine closed in June 1973. Mineralogically it is an important locality, with over 60 mineral species known from the deposit.