Hollandite Quartz: Urchin Quartz

Hollandite Quart also known as, Urchin Quartz, is a type of quartz crystal that contains tiny black inclusions of the mineral hollandite. These inclusions resemble tiny stars, giving the quartz its characteristic spiky appearance.

Urchin Quartz, also known as Star Quartz or Hollandite Quartz, is a rare and unique variety of quartz that is characterized by tiny black or dark gray inclusions of the mineral Hollandite. These inclusions, which resemble tiny stars or sea urchins, give the quartz its distinctive appearance. Urchin Quartz typically forms in shades of white, milky white, or creamy white, but it can also exhibit pinkish, reddish, or brownish inclusions.

Hollandite Quartz formations are formed when deposits of Hollandite become trapped within Quartz during its formation. As the Hollandite becomes subjected to high thermal temperatures within the Earth, the Hollandite bursts into star formations within the Quartz. This variety of quartz is very rare.

Urchin Quartz (Quartz crystal with Mannardite phontom inside) from Brazil
Photo: Mike Bowers

How Hollandite Quartz is Formed

The exact formation process of Urchin Hollandite Quartz is still being studied by geologists, but it is believed to arise from a combination of factors, including:

Hydrothermal Conditions: Urchin Quartz is often found in hydrothermal veins, which are fractures in rocks that have been filled with hot, mineral-rich fluids. These fluids provide the necessary conditions for quartz crystals to grow and form.

Inclusions of Hollandite: Hollandite, the mineral that forms the tiny inclusions in Urchin Quartz, is typically found in association with quartz in hydrothermal veins. The Hollandite becomes trapped within the growing quartz crystals, giving them their distinctive appearance.

Specific Chemical Environment: The presence of certain chemicals in the hydrothermal fluids, such as barium or manganese, may influence the incorporation of Hollandite inclusions into the quartz crystals.

Hollandite Quartz Properties

Color: White, milky white, creamy white, pinkish, reddish, brownish, with black or dark gray inclusions
Transparency: Translucent, opaque
Luster: Vitreous, waxy
Hardness: 7
Specific Gravity: 2.65
Cleavage: None
Fracture: Irregular, conchoidal
Crystal System: Hexagonal
Chemical Formula: SiO2 (quartz) + Ba(Mn⁴⁺₆Mn³⁺₂)O₁₆ (hollandite)
Origin: Hydrothermal veins

Hollandite

Hollandite is a manganese oxide mineral with a chemical formula of Ba(Mn⁴⁺₆Mn³⁺₂)O₁₆. It is a black to silvery-grey mineral with a metallic luster. Hollandite is a member of the hollandite supergroup, which includes a variety of manganese oxide minerals with similar structures. Hollandite is a relatively rare mineral, and it is found in a variety of geological settings, including hydrothermal veins, manganese deposits, and contact metamorphic rocks.

Photo Credit : dusted77

Hollandite is formed in a variety of geological settings, including hydrothermal veins, manganese deposits, and contact metamorphic rocks. In hydrothermal veins, hollandite is formed as hot, mineral-rich fluids precipitate minerals along fractures in rocks. In manganese deposits, hollandite is formed as manganese-rich sediments are compacted and cemented. In contact metamorphic rocks, hollandite is formed as manganese-rich rocks are heated and altered by contact with magma.

Urchin Quartz - Hollandite Quartz Uses

Jewelry: Urchin Quartz is a popular gemstone and is often cut into cabochons or beads and used in necklaces, earrings, bracelets, and rings.

Carvings and decorative objects: Urchin Quartz is sometimes used in carvings and other decorative objects.

Metaphysical healing: Urchin Quartz is sometimes used in healing practices, such as meditation and crystal healing. It is believed to have a number of metaphysical properties, including promoting peace, tranquility, and creativity.