Lazulite Mineral Overview

• Mineral name: Lazulite
• Mineral class: Phosphate
• Chemical formula: (Mg,Fe²⁺)Al₂(PO₄)₂(OH)₂
• Crystal system: Monoclinic
• Mohs hardness: 5.5–6
• Color range: Deep blue, blue-violet, azure
• Luster: Vitreous
• Streak: White
• Cleavage: Poor
• Fracture: Uneven
• Specific gravity: Approximately 3.0–3.1
• Transparency: Transparent to opaque
• Common locations: Austria, Brazil, United States, Switzerland
• Uses: Collector mineral, minor gemstone
• Similar minerals: Azurite, lazurite, sodalite

Naming and Classification

Lazulite is a magnesium iron aluminum phosphate mineral, named from the Arabic lazaward, meaning “blue,” referring to its rich blue color.

Despite the similar name, it is not directly related to lazurite, the primary component of lapis lazuli.

Physical and Optical Characteristics

Lazulite typically occurs as:

• Short prismatic or bipyramidal crystals
• Massive or granular aggregates

Its most distinctive feature is its deep blue to blue-violet color, which can appear:

• Rich azure blue
• Darker indigo tones
• Slightly greenish-blue in some specimens

The luster is vitreous, giving crystals a glassy shine.

With a Mohs hardness of 5.5–6, lazulite is moderately hard.

Color Origin

The blue coloration is primarily due to:

• Iron (Fe²⁺) within the structure

Variations in iron and magnesium content can influence the exact shade of blue.

Chemical Composition and Structure

Lazulite is composed of:

• Magnesium (Mg)
• Iron (Fe²⁺)
• Aluminum (Al)
• Phosphate groups (PO₄)
• Hydroxyl (OH)

It is part of a group of phosphate minerals formed under metamorphic conditions.

Formation and Geological Occurrence

Lazulite forms in metamorphic environments, particularly in:

High-Grade Metamorphic Rocks

• Quartzites
• Aluminum-rich rocks

Hydrothermal Systems

• Less commonly in veins

Typical formation conditions include:

• Moderate to high temperatures
• Phosphate-rich environments

It is commonly associated with:

• Quartz
• Kyanite
• Andalusite
• Other phosphate minerals

Common Locations

Lazulite is found in several notable regions:

• Austria: Alpine deposits (classic locality)
• Brazil: High-quality specimens
• United States: Georgia, Colorado
• Switzerland: Alpine metamorphic مناطق

Brazilian specimens are especially valued for color.

Uses and Practical Significance

Lazulite is used primarily for:

Collector Specimens

• Attractive blue crystals
• Geological interest

Gemstone Use

• Occasionally cut into cabochons
• Limited due to rarity and cleavage

It has no industrial use.

Similar and Related Minerals

Lazulite can resemble:

• Azurite: Softer and more vibrant blue
• Lazurite: Associated with lapis lazuli
• Sodalite: More uniform blue and less crystalline

Crystal form and geological setting help distinguish lazulite.

Identification Notes for Collectors

• Look for deep blue prismatic crystals
• Note moderate hardness (5.5–6)
• Observe vitreous luster
• Check association with metamorphic rocks
• Distinguish from azurite by hardness and crystal habit

Lazulite is a phosphate mineral, recognized for its rich blue coloration and formation in metamorphic environments, making it a visually striking and desirable specimen for collectors.