Secrets About Mining Herkimer Diamond Quartz Crystals

Introduction to Herkimer Diamonds

• Definition: Herkimer diamonds are doubly terminated quartz crystals found mainly in Herkimer County, New York.
• Characteristics: These crystals are known for their double terminations which occur due to the crystal growing with minimal contact with host rock.
• Rarity: Doubly terminated crystals are rare, making Herkimer diamonds highly valued by collectors.

Geology and Geography

• Host Rock: Found in Cambrian-age Little Falls Dolostone, deposited about 500 million years ago.
• Formation: Formed in cavities lined with drusy quartz within dolostone, often featuring hydrocarbon coatings.
• Other Locations: Similar crystals found in Arizona, Afghanistan, Norway, Ukraine, and China.

Discovery and History

• Early Discoverers: Mohawk people and early settlers found the crystals in streams and fields.
• Historical Use: Used as amulets and traded with other tribes; interest waned with the arrival of European glass beads.

Physical Properties

• Chemical Classification: Silicate
• Color: Colorless to smoky
• Hardness: Mohs hardness of 7
• Specific Gravity: 2.6 to 2.7
• Crystal System: Trigonal
• Uses: Collectors' items, natural crystal jewelry, holistic gemstones, and tourist souvenirs.

Mining Herkimer Diamonds

• Popular Mining Locations: Along New York State Routes 28 and 29, near Middleville.
• Commercial Mines: Ace of Diamonds Mine, Herkimer Diamond Mines, Crystal Grove Diamond Mine.
• Legal Considerations: Collecting minerals on government land is illegal; permission required on private property.

Mining Methods

• "Find and Break" Prospecting: Breaking vuggy rocks to discover Herkimer diamonds within. Requires safety gear due to the hardness of dolostone.
• "Scavenger" Prospecting: Searching rock rubble and quarry floor for loose crystals; safe for kids.
• "Cavity" Prospecting: Breaking into quarry walls to find crystal-rich cavities using hammers and wedges.

Misnomer of Herkimer Diamonds

• "Herkimer diamond" is a misnomer as they are quartz, not diamonds.
• The name persists due to tradition and marketing appeal.

Conclusion and Recommendations

• Enjoyment: Mining for Herkimer diamonds is a fun activity, offering anticipation and satisfaction of finding quartz crystals.
• Safety and Preparation: Proper clothing, safety glasses, gloves, and tools are recommended.
• Access: For those unable to visit, online resources like HerkimerDiamonds.ca offer purchase options.

Additional Resources

• Books and Guides: Collector's Guide to Herkimer Diamonds by Michael R. Walter, and Mineralogy of New York by Lewis C. Beck.
• Online Resources: Geology.com offers further information and related topics on minerals and geology.