Quartz
specimen number:
8311463
location:
Middleville, Herkimer Co., New York, USA
description: Glassy gem quality crystals of quartz to 2.0 cm in size aesthetic up on matrix. These are often called Herkimer diamonds. This one is in excellent condition, there are no repairs. Middleville, located in Herkimer County, New York, is globally recognized for its exceptional quartz specimens, famously known as Herkimer Diamonds. Geologically, these double-terminated, exceptionally clear crystals formed within vugs and cavities of the Little Falls Dolostone, a Cambrian-aged sedimentary rock unit. The crystals precipitated from hydrothermal fluids approximately 300 to 400 million years ago, often occurring alongside dark, carbonaceous material known as anthraxolite. Historically, while the local indigenous peoples and early settlers were aware of the crystals, organized mining and quarrying for mineral specimens gained momentum in the 19th century. Various commercial and fee-for-dig operations, such as the Ace of Diamonds Mine and Herkimer Diamond Mines, have operated intermittently since the mid-1900s to the present day. As of 2026, the area remains a premier destination for both professional mineralogists and amateur collectors who visit the active quarries to extract these lustrous, hard-rock quartz crystals from the tough dolostone matrix.
Size: 4.0 x 3.5 x 3.0 cm (miniature)
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Related by Mineral (Quartz):
Quartz — Sweden
Origin: Smedjebacken, Dalarna, Sweden
Number: (9302282)
Size: 6.5 x 3.5 x 3.0 cm (small-cabinet)
Quartz — China
Origin: Jinlong hill, Longchuan Co., Heyuan, Guangdong, China
Number: (9506458)
Size: 8.5 x 5.0 x 4.0 cm (small-cabinet)
Quartz — Brazil
Origin: Vaca Morta quarry, Bahia, Brazil
Number: (1713764)
Size: 2.2 x 2.0 x 1.8 cm (thumbnail)

