Hydrothermal and Metamorphic Environment main content.

Hydrothermal and Metamorphic Environment

Part of Harry Frank Guggenheim Hall of Minerals.


Exhibition Text

The development of a mineral deposit may involve more than one kind of environmental condition. The world-famous and valuable zinc-manganese-iron ore deposit 50 miles northwest of New York, in the Franklin-Sterling Hill area of New Jersey, is an excellent example. About 230 mineral species, a record number, have been found in a complex geologic situation that probably involved both hydrothermal and metamorphic mineral-forming activities. Samples of the ore rock, its contained ore minerals, and other outstanding mineral specimens are displayed here.

Audio Transcript
These three cases deal with a collection of minerals that geologists think may be the result of the interaction of processes at work in more than one kind of environment. In all probability, the minerals shown here were developed through the processes involved in both the hydrothermal and metamorphic environments.

Approximately 50 miles Northwest of New York City, in New Jersey, is a very famous mineral locality the town of Franklin. It's an area where zinc had been mined until 1954. Zinc mining still continues near Franklin, at Sterling Hill in Ogdensurg.

What makes the Franklin Sterling hill locality unusual is the vast variety of mineral species that have been found here — some 230, which is close to being a world's record. Additionally, many of the minerals, such as the Franklinite, the zincite, and the willemite, have not been found in any abundance elsewhere in the world.

And to make the area even mo