Pyrite: meaning, properties and lore

The mineral

Pyrite is an iron sulfide with the ideal chemical composition FeS2, and it is also called iron pyrites and recorded as iron bisulphide. It belongs to the isometric crystal system and is described as the cubic sulphide FeS2. Its sulphur content is 53.4 per cent and its density is about 5.02 g/cc. Pyrite is distinguished from pyrrhotite, a lower sulphide of iron often termed magnetic pyrite.⁸³⁴¹²⁹

Pyrite is brittle and has a pronounced conchoidal fracture that produces sharp fragments. Its Mohs hardness is 6. It is a semiconductor whose conduction can be n type or p type. Pyrite crystallises over a wide temperature range and forms cubes, prisms, octahedra, pyritohedra and granular masses, and its morphology depends on growth parameters such as temperature and degree of supersaturation.⁴³

A pseudo-icosahedral form often found in pyrite is a combination of a regular octahedron and an irregular pentagonal dodecahedron known as a pyritohedron. A regular icosahedron cannot exist in a crystal because it contradicts Haüy's law of rational indices. Marcasite is the low temperature, chemically unstable, orthorhombic dimorph of pyrite. Its colour, luster and shape are characteristic of the mineral.³⁴

Pyrite forms in sedimentary rocks and occurs commonly in Pennsylvanian black shales, both finely disseminated and as irregular concretionary masses. The pyritic cone-in-cone concretions studied occur in Middle Pennsylvanian black shales of Indiana and Illinois. In the Indiana concretions the core is earthy, phosphatic material, probably coprolitic, rather than pyrite.⁸⁶

Pyrite is found massively in the Rio Tinto deposits of Huelva Province, Spain, where it has been open cut mined for millennia. Pyrite is also a primary mineral in the volcanic and subvolcanic units of the Neyshabur mine. Pyrite occurs in the sulfide-bearing veins of the region at Thunder Bay, Ontario, which are primarily galena with minor to trace sphalerite and chalcopyrite.⁴¹⁰⁷

Pyrite occurs as euhedral crystals up to 1 mm included within amethyst from La Manche, Newfoundland. These inclusions are relatively rare, and they are flattened or have a more complex morphology, showing a combination of cubic, octahedral and possibly pyritohedral faces. Pyrite inclusions at Thunder Bay occur alongside chalcopyrite in amethyst with spherulitic hematite and acicular goethite.⁷

Pyrite is sometimes found as an inclusion in emeralds from various countries. Pyrite was identified as a black metallic opaque inclusion in Bing Piao red agate from Liangshan, where its particles appear as blades and planar clusters. Its composition was matched by a Raman spectrum and SEM-EDS analysis, and EBSD analyses indicated a cubic structure.³¹¹

History and lore

Pliny the Elder described pyrites in his Naturalis Historia, discussing its medical uses. Marbod, Bishop of Rennes, included a four-line poem De Pyrite in his lapidary compiled between 1061 and 1081. The name pyrites derives from the Greek word for fire, and Bronze Age and early humans struck it with flint to make fire, as shown by the kit of Ötzi man found in 1991. Pyrite was used in wheel lock pistols in the 1500s to ignite gunpowder.⁴

The ancient Mexicans wrought pyrite into mirrors and other ornamental objects, with the convex side often carved and decorated. Two notable pyrite objects are a human head with white chalcedony eyes in the U.S. National Museum (Blake collection) and two human skulls encrusted with turquoise in the Christy collection, London. The place in Mexico where pyrite suitable for carving once occurred appears to have been entirely lost.¹

Goniometric studies by Romé de L'Isle from 1783 showed the pseudo-icosahedral form of pyrite to be a combination of an octahedron and a pyritohedron. Brogger (1882) considered the fibrous pyrite of Oslo region concretions to be a replacement of original fibrous calcite, while Antun (1967) considered the pyrite in Oslo region cone-in-cone to be original rather than replacement.³⁶

Cordiner, writing at the beginning of the nineteenth century, recorded that crystallized pyrites containing a little copper was manufactured into buttons. Percival's contemporary account of Ceylon notes that Stahltein, or crystallized pyrites impregnated with a little copper, was used by the Singhalese for making buttons. Dr. Gygax described iron pyrites occurring in oblong flat knells along the stratification of grey granite, pale and nearly silver-white.¹²

The First Prose Lapidary states that pyrites is pale (falve) and does not like to be gripped, because it burns the hand that squeezes it. Isidore describes a common pyrites that gives off sparks when struck with iron or stone, and that the common people call a fire-stone. Pyrites is described as having a pale yellow, brassy colour (falve) in the Anglo-Norman lapidary tradition.⁵

The Alphabetical Lapidary says pyrites is named for its nature and is used in medicine, and that anyone who drinks it with water and washes the eyes is healed. The commentary notes that the source of the link between pyrites and jet in that lapidary is unknown, and says the account is doubtful as to source.⁵

Birthstone, zodiac and chakra links

Some crystal enthusiasts align pyrite with the zodiac signs Aries, Leo, Scorpio and Capricorn, and the zodiac link with Leo and the planet Mars is a modern practitioner link. Crystal practitioners say pyrite is tied to the solar plexus chakra, a link they describe as modern.¹³¹⁴¹⁵

What crystal practitioners say

Crystal practitioners associate pyrite with abundance and prosperity, and it is widely regarded as a symbol of good luck alongside those ideas. Within this tradition, the stone is believed to carry an energy that can draw in wealth, success and opportunities.¹⁵¹⁴

According to crystal practitioners, pyrite is used as a manifestation tool that helps clarify intentions and strengthen focus. Its supporters believe it helps a person overcome self-limiting beliefs and embrace inner power, and when paired with grounded determination it is said to support purposeful goal planning. Practitioners also say it can anchor frenetic thoughts.¹⁵¹³

Believers hold that pyrite is a powerful protector that shields against negative energies and environmental pollutants. Users commonly place pyrite near electronics to lessen possible energetic disturbances. Believers in New Age lore say a hunk of pyrite placed on a conference table invigorates the ambience and optimises decisions.¹⁵¹³⁴

Crystal practitioners advise cleansing pyrite with a dry method such as smudging with sage or sound vibrations, since water can damage its surface. Pyrite is said to keep specimens from turning black when cut only with water, according to the Gemological Institute of America.¹⁴⁸

Believers say pyrite synchronizes with planetary influences related to personal power and prosperity, and crystal practitioners say it grounds the root chakra as well as the solar plexus.¹³

What testing has found

Rigorous scientific research into crystal therapy is lacking, and few studies have compared it to other therapies, and the scientific community remains skeptical of crystal therapy.¹⁶¹⁷

A 2001 double-blind study by Chris French tested 80 participants meditating with either a real quartz crystal or a fake glass crystal. Participants showed a placebo effect, feeling what they were primed to feel, such as warmth, tingling or well-being, and could not tell real crystals from fake ones. Six people felt nothing, while the rest reported sensations, with similar reports from both groups.¹⁸¹⁶

Some researchers suggest that crystals probably do not act directly on physical or psychological complaints, and that any benefit may instead stem from the placebo effect. Ted Kaptchuk has noted that placebo responses in unconventional medicine can be striking and particularly persuasive from the patient's standpoint. Because the 2001 crystal study has not been repeated in larger trials, its findings are difficult to generalise.¹⁷