"Herkimer-style" Quartz

A variety of Quartz

This is a collective name to group together the many different local names for transparent, lustrous quartz crystals, usually doubly-terminated, often associated with inclusions of petroleum and/or associated with oil or coal deposits within sedimentary rocks. All such quartz crystals formed under low-temperature hydrothermal conditions in the sedimentary rocks.
Rarely, these quartzes form also as sceptres.

The misleading name Herkimer Diamond has been used locally in the Herkimer region of New York State, USA to describe such crystals since the early 20th century and possibly longer.

Apart from the confusion that these are actually quartz rather than diamond there has been growing confusion and arguments in more recent times as the name 'Herkimer diamond' is increasingly associated with other similar quartz crystals from other regions, including those from Hungary, France, Italy, Austria, Canada, Pakistan, China and others.