Marcasite For Sale

Marcasite is an iron sulfide mineral (FeS₂) known for its metallic luster and distinct crystal forms. Often mistaken for pyrite, marcasite has a paler, more brassy hue and tends to form in unique, sharp, spear-like crystals or delicate clusters resembling cockscombs. These formations can give marcasite a fascinating, almost geometric appearance, with surfaces that reflect light in a way that gives it a shimmering metallic quality.

More About Marcasite

3 Items ($595 to $695)

Colorful Polished Marcasite Agate Sphere - Indonesia #308259

3.9" Colorful Polished Marcasite Agate Sphere - Indonesia

$695

Colorful Polished Marcasite Agate Slab - Indonesia #303455

7.4" Colorful Polished Marcasite Agate Slab - Indonesia

$595

Colorful Polished Marcasite Agate Sphere - Indonesia #308201

1.68" Colorful Polished Marcasite Agate Sphere - Indonesia

SOLD

More About Marcasite

Marcasite is an iron sulfide mineral with the chemical formula FeS₂, the same as pyrite. However, despite having the same chemical composition, marcasite and pyrite differ structurally. Marcasite has an orthorhombic crystal structure, whereas pyrite crystallizes in the isometric system. This structural difference not only affects their appearance but also their stability. Pyrite is more stable, while marcasite is prone to alter over time, especially in humid conditions. Visually, marcasite stands out due to its pale brass color and high metallic luster. Its crystal formations range from sharp spear-like shapes to beautiful radiating clusters, often called “cockscomb” or “petal-like” forms. These formations make it particularly desirable to collectors who appreciate its distinct appearance.

Marcasite typically forms in low-temperature, acidic environments, often in sedimentary rock formations like limestone, shale, and marl. It can also occur as a secondary mineral in hydrothermal veins. Unlike pyrite, which is stable over a wide range of temperatures and pH levels, marcasite requires very specific conditions to form, which makes well-formed specimens rarer and more sought after. Some well-known locales for marcasite specimens include sedimentary deposits in France, England, and the United States, particularly Illinois. It also occurs in various other parts of the world, often in association with minerals like calcite, fluorite, and galena. In some places, marcasite is found as small, decorative nodules or nodular formations that resemble clusters of roses, adding to its appeal as a collectible mineral.

Physical and Chemical Properties

Marcasite is recognized for its:

Color: A pale brass or yellowish metallic hue, distinct from pyrite’s brighter gold tone.

Crystal Form: Orthorhombic crystal system, forming sharp, tabular, or spear-like crystals and sometimes intricate radiating clusters.

Luster: Metallic, which gives marcasite a shimmering appearance.

ardness: Around 6–6.5 on the Mohs scale, similar to pyrite.

Specific Gravity: Approximately 4.9, making it relatively dense for its size.

A key feature of marcasite is its susceptibility to decay over time due to oxidation. When exposed to moisture, it can alter and release sulfuric acid, causing the mineral to disintegrate slowly. This is known as the “marcasite disease,” a form of alteration that makes it difficult to preserve in collections. As a result, quality specimens are considered highly desirable.

Uses and Cultural Significance

Although marcasite’s brittleness makes it challenging to cut and polish, it has been used in jewelry for centuries. In the Victorian era, marcasite was commonly used as a decorative stone, set into brooches, rings, and other items due to its metallic sheen. This historic jewelry often used “pyrite marcasite,” which was pyrite fashioned to resemble marcasite.

Today, marcasite jewelry and decorative items are less common, but the mineral still holds interest in the metaphysical community. Marcasite is believed by some to have grounding and clarifying properties, helping one to feel stable, balanced, and protected. It’s often seen as a symbol of resilience and determination, making it a meaningful stone for those interested in crystal healing and metaphysics.

Caring for Marcasite

Its unique shapes and metallic shine make it a standout in any collection, but proper care is essential to prevent it from degrading over time. Storing marcasite in a dry, climate-controlled environment is crucial, as humidity can accelerate its breakdown.

More About Marcasite

Physical and Chemical Properties

Uses and Cultural Significance

Caring for Marcasite