Herkimer "diamond" (variety of quartz)

Mineral formula: SiO₂

Mineral group: member of the silicate group

Crystal system: trigonal

Crystal habit: prismatic with numerous habits in additional to the “normal” six-sided one.

Cleavage: none

Fracture: conchoidal

Color: clear, sometimes with black/dark grey carbonaceous inclusions

Luster: adamantine to vitreous

Diaphaneity: transparent

Moh’s scale hardness: 7

Streak: none (harder than streak plate)

Specific gravity: 2.65 – 2.66

Named after: the type locality, Herkimer County, New York. It was called “diamond” due to the unusually lustrous, adamantine luster of these crystals. They were originally (1790) named "Little Falls Diamond(s)"

Type locality: Herkimer County, New York

Geological occurrence:  clear and highly lustrous, quartz crystals from cavities in dolostones in Herkimer Co., New York, and surrounding areas, USA. They are frequently doubly terminated with prism faces about as prominent as the pyramidal terminations. This type of quartz forms under low-temperature hydrothermal conditions in sedimentary rocks and often contain hydrocarbon inclusions.

Energetic properties: Working with Herkimer quartz is like working with regular quartz, on steroids; some consider them to the most powerful of all quartz crystals.