This is a specimen with a lot going on. At first glance it is most obviously a fine analcime specimen. The larger analcime crystals are the first generation of analcime crystals – they are share and highly lustrous. In association there are wonderful tabular crystals of glassy hydroxyapophyllite-(K) crystals. The specimen is then dusted throughout with sparkling tiny second-generation analcime crystals – under magnification, one can see that the sparkle effect is enhanced because they are transparent. At the top of the specimen (as photographed) there is a group of needle-like natrolite crystals, and with the loupe one can also spot a few in other places on the piece. Upon close inspection with magnification, one can see small crystals of laumontite and a chlorite group mineral as well.
In excellent condition – no damage, and just one contacted analcime at lower left, where it was attached to the original rock (the contact is on the underside of the specimen as displayed and not seen). A beautiful Cornwall Iron Mine analcime and hydroxyapophyllite-(K) from the John S. White Pennsylvania Collection.
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.