Herkimer diamond
Encyclopedia
Double Terminated Crystal
A double terminated crystal is a crystal with two naturally faceted ends. It is a rarer form of crystal as it forms free-floating in pockets of clay, rather than on one side of a stone...
quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
crystal discovered within exposed outcrops of dolostone
Dolostone
Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is...
in and around Herkimer County, New York
Herkimer County, New York
Herkimer County is a county located in the U.S. state of New York. It was created in 1791 north of the Mohawk River out of part of Montgomery County. As of the 2010 census, the population was 64,519. It is named after General Nicholas Herkimer, who died from battle wounds in 1777 after taking part...
and the Mohawk River
Mohawk River
The Mohawk River is a river in the U.S. state of New York. It is the largest tributary of the Hudson River. The Mohawk flows into the Hudson in the Capital District, a few miles north of the city of Albany. The river is named for the Mohawk Nation of the Iroquois Confederacy...
Valley. Because the first discovery sites were in the village of Middleville
Middleville, New York
Middleville is a village in Herkimer County, New York, New York. The population was 550 at the 2000 census.The Village of Middleville is on the boundary of the Towns of Newport and Fairfield. The village is north of the Village of Herkimer and is east of Utica.- History :The community was first...
and in the city of Little Falls
Little Falls (city), New York
Little Falls is a city in Herkimer County, New York, USA. The population was 5,188 at the 2000 census. The name is derived from a small cataract near the city....
, respectively, the crystal is also known as a Middleville diamond or a Little Falls diamond.
Herkimer diamonds became largely recognized after workmen discovered them in large quantities while cutting into the Mohawk River Valley dolostone in the late 18th century. Geologists discovered exposed dolostone in Herkimer County and began mining there. The popularity of mining for double-terminated quartz in the Herkimer County outcroppings is what led to the name, Herkimer diamonds. Currently, Herkimer diamonds can be found in large quantity in at least Herkimer, Fulton
Fulton County, New York
Fulton County is a county located in the U.S. state of New York. As of the 2010 census, the population was 55,531. Its name is in honor of Robert Fulton, who is widely credited with developing the first commercially successful steamboat...
, and Montgomery
Montgomery County, New York
As of the census of 2000, there were 49,708 people, 20,038 households, and 13,104 families residing in the county. The population density was 123 people per square mile . There were 22,522 housing units at an average density of 56 per square mile...
counties, and double-pointed quartz crystals have also been found in abundance, in Tibet and Afghanistan as well as in other countries.
Many of the New York crystals are known for their extreme clarity, and Wicca
Wicca
Wicca , is a modern Pagan religious movement. Developing in England in the first half of the 20th century, Wicca was popularised in the 1950s and early 1960s by a Wiccan High Priest named Gerald Gardner, who at the time called it the "witch cult" and "witchcraft," and its adherents "the Wica."...
n and New Age
New Age
The New Age movement is a Western spiritual movement that developed in the second half of the 20th century. Its central precepts have been described as "drawing on both Eastern and Western spiritual and metaphysical traditions and then infusing them with influences from self-help and motivational...
belief systems often ascribe specific occult
Occult
The word occult comes from the Latin word occultus , referring to "knowledge of the hidden". In the medical sense it is used to refer to a structure or process that is hidden, e.g...
properties and a wide variety of mystical powers to them.
These quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
crystals, which geologists theorize formed extremely slowly in small solution cavities or vug
Vug
Vugs are small to medium-sized cavities inside rock that may be formed through a variety of processes. Most commonly cracks and fissures opened by tectonic activity are partially filled by quartz, calcite, and other secondary minerals. Open spaces within ancient collapse breccias are another...
s, have 18 facets (6 sides) and two terminations. There are also larger cavities that are several feet in diameter that are called "pockets". They can be found clear, cloudy, smoky or even containing a variety of rare impurities. Impurities (rare and general) can include cluster
Cluster
-In science:* Cluster , a small group of atoms or molecules* Cluster chemistry, an array of bound atoms intermediate in character between a molecule and a solid...
s, scepters, enhydro
Enhydro agate
Enhydro Agate is agate that has water with an air bubble in it or they have been broken open. You can see the crystalline center of the broken geode. The water inside the whole ones has been trapped there for millions of years....
(properly called fluid inclusions
Fluid inclusions
thumb|250px|Trapped in a time capsule the same size as the diameter of a human hair, the ore-forming liquid in this inclusion was so hot and contained so much dissolved solids that when it cooled, crystals of halite, sylvite, gypsum, and hematite formed. As the samples cooled, the fluid shrank more...
), phantom
Phantom crystal
Phantom quartz is a variety of quartz, or "rock crystal", that, over the course of millions of years, forms over earlier rock crystals that already existed. It takes its name from the particular structure of its crystallization: each crystal displays the outlines of numerous smaller crystals, known...
, and bridge crystals. A fluid inclusion contains a water pocket (plus methane or oil, and rarely a crystal) within the crystal, a phantom is a crystal which contains an image of itself within, a skeletal crystal contains a series of crystal edge outlines inside the crystal and a hopper crystal has its faces replaced by a step like pattern.