Herkimer Diamond
Quartz var. Herkimer Diamond · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Trigonal system, doubly terminated prismatic crystal habit with 18 crystal faces
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal and diagenetic formation within cavity pockets of the Cambro-Ordovician Little Falls Dolostone at low temperatures
About This Crystal
A small, transparent, doubly terminated colorless quartz crystal displaying exceptional clarity and natural brilliance, resembling a cut diamond with sharp hexagonal prism faces and terminal pyramids at both ends
Physical Characteristics
Colorless, white streak, no cleavage, conchoidal fracture, specific gravity of 2.65, brittle tenacity, piezoelectric, and typically exhibits weak blue or orange fluorescence under shortwave UV light
Optical Properties
Uniaxial positive optic sign, doubly refractive, refractive index of 1.544 to 1.553, low birefringence of 0.009, with no pleochroism due to being colorless
Hardness & Durability
Origin Region
Herkimer County, New York, USA, found in exposed dolostone outcrops
Hardness & Durability
Mohs hardness of 7, good durability and toughness, suitable for various types of jewelry although secure settings are recommended
Care & Maintenance
Safe to clean with warm soapy water and soft brushes, avoid harsh chemicals or sudden thermal shock, store separately to prevent scratching softer gemstones
Rarity & Value
Commonly found in its local region but fine, flawless specimens are valued by collectors, ranging from affordable to moderately priced based on clarity and size
Special Characteristics
Naturally doubly terminated with 18 faces, often contains hydrocarbon inclusions (anthraxolite), gas bubbles, or water-filled pockets known as enhydros
Lore & History
Historically used by the Native American Mohawk people as amulets and tools; in modern metaphysical practices, it is considered a high-frequency crystal associated with the crown chakra, believed to amplify spiritual energy and clarity