Brazilian quartz points

Name: Brazilian quartz points
SKU: 893
Availability: InStock

£60.00

Brazilian quartz points are naturally occurring α-quartz (SiO₂) crystals that crystallize in the trigonal crystal system. They typically form hexagonal prisms terminated by pyramidal faces, representing one of the clearest and most well-developed examples of quartz crystallization globally.

Formation and Geological Context

Quartz points from Brazil form primarily in hydrothermal veins, pegmatites, and granitic cavities.
Crystallization occurs from silica-saturated aqueous fluids under stable temperature and pressure conditions.
Variations in growth rate, fluid chemistry, and supersaturation produce features such as growth zoning, phantom layers, and internal fluid inclusions, which preserve records of changing environmental conditions during formation.
Large, clear crystals are indicative of slow, undisturbed crystallization, allowing the development of sharp, well-defined terminations.

Physical and Crystallographic Properties

Chemical formula: SiO₂
Crystal system: Trigonal
Hardness: 7 (Mohs scale)
Density: ~2.65 g/cm³
Cleavage: None; fracture: conchoidal
Luster: Vitreous

Categories: Clear Quartz, Crystals, Quartz Tag: quartz

Description
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Description

Brazilian quartz points are naturally formed α-quartz (SiO₂) crystals exhibiting well-defined prismatic habits with sharp terminations. These crystals crystallize in the trigonal crystal system, typically forming hexagonal prisms capped by pyramidal faces.

Formation and Properties

Chemical composition: SiO₂
Hardness: 7 (Mohs scale)
Luster: Vitreous
Transparency: Transparent to translucent
Cleavage: None; fracture: conchoidal
Crystals grow from silica-saturated hydrothermal fluids in pegmatitic or granitic environments. Variations in temperature, pressure, and fluid composition influence the clarity, size, and formation of terminations.

Geological Significance

Quartz points from Brazil, particularly from Minas Gerais, are renowned for their large size, clarity, and well-formed terminations.
They represent slow, stable crystallization in silica-rich environments over millions of years, often recording subtle growth zoning or fluid inclusions.

Educational Value

Excellent examples for studying crystal growth habits, optical properties, and the effects of hydrothermal conditions on mineral formation.
Frequently used in mineral collections, teaching specimens, and geological study due to their clarity and well-developed morphology.

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