Herkimer Diamond (Quartz)
Quartz (Silicon Dioxide) var. Herkimer Diamond · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Trigonal; typically doubly terminated (hexagonal-appearing) bipyramidal prisms with missing or short stems
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with possible trace hydrocarbons and carbonaceous inclusions
Formation Process
Hydrothermal; formed in vugs (cavities) within the Little Falls Dolostone during the Cambrian period, roughly 500 million years ago
About This Crystal
A highly transparent, colorless to slightly smoky quartz variety with an exceptionally high vitreous luster. This specimen shows characteristic internal fractures and black anthraxolite (hydrocarbon) inclusions.
Physical Characteristics
Color: Colorless/Clear; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Often shows weak yellow or orange-white fluorescence under LWUV due to hydrocarbon inclusions.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Doubly Refractive (uniaxial positive); Dispersion: 0.013
Hardness & Durability
Origin Region
Herkimer County, New York, USA (and surrounding Areas such as Mohawk River Valley)
Hardness & Durability
Mohs Hardness: 7.0; Toughness: Fair to Good; very stable for daily jewelry wear but can shatter upon high impact due to internal inclusions.
Care & Maintenance
Safe to clean with warm soapy water or ultrasonic cleaners. Safe from sunlight fading, but avoid extreme thermal shock which may expand internal fluid or gas inclusions.
Rarity & Value
Relatively common in its locality but high-quality, perfectly clear, doubly terminated specimens are valued by collectors. Generally priced by clarity and size ($5 to $500+).
Special Characteristics
Often contains 'enhydros' (trapped water bubbles) or anthraxolite (black coal-like specks). Known for its natural 'faceted' appearance without human cutting.
Lore & History
Historically used by the Mohawk people and early settlers. Metaphysically known as the 'Stone of Attunement,' believed to amplify energy and link the physical/spiritual planes.