Marble vs Granite vs Quartzite: The Architect's Specification Guide

Quick Comparison

| Property | Marble | Granite | Quartzite |

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Mohs Hardness

3-4

6-7

7-8

Density (kg/m³)

2,500-2,700

2,600-2,800

2,600-2,700

Water Absorption

0.2-0.5%

0.1-0.3%

0.1-0.2%

Thermal Conductivity

2.5-3.0 W/mK

2.5-3.5 W/mK

5.0-7.0 W/mK

Price Range (€/m²)

80-500+

60-300

100-400

| Color Consistency (ΔE) | 2.0-5.0 | 1.5-3.0 | 1.0-2.5 |

Marble: Timeless Elegance with Considerations

Best Applications

- Interior flooring (low-traffic) - Wall cladding - Bathroom vanities - Sculptural elements - Luxury residential

Technical Specifications

Marble is metamorphic limestone, primarily composed of calcite (CaCO₃). Its relatively low hardness (3-4 Mohs) makes it susceptible to scratching and etching from acidic substances.

According to ASTM C503, architectural marble should meet: - Absorption: Max 0.20% (Class I) to 0.75% (Class IV) - Compressive strength: Min 52 MPa - Flexural strength: Min 7 MPa

Color Matching Challenges

Marble presents the highest color variation among premium stones. Delta-E values between adjacent slabs can range from 2.0-5.0, making scientific color matching essential for large projects.

The International Institute of Marble, Stone and Restoration recommends: - Specifying maximum ΔE tolerance in contracts - Requiring slab approval before fabrication - Documenting color profiles digitally

Maintenance Requirements

- Seal every 6-12 months - pH-neutral cleaners only - Immediate spill cleanup - Professional honing for scratches

Granite: The Workhorse Premium Stone

Best Applications

- Kitchen countertops - High-traffic flooring - Exterior cladding - Commercial spaces - Outdoor installations

Technical Specifications

Granite is an igneous rock composed primarily of quartz, feldspar, and mica. Its high hardness (6-7 Mohs) and low porosity make it ideal for demanding applications.

Per ASTM C615, architectural granite should meet: - Absorption: Max 0.40% - Compressive strength: Min 131 MPa - Flexural strength: Min 10.34 MPa

Color Consistency Advantage

Granite typically shows better batch-to-batch consistency than marble, with Delta-E values of 1.5-3.0 between slabs from the same quarry. This makes it easier to match for large commercial projects.

Regional Sourcing Considerations

The Natural Stone Institute's 2024 sourcing guide highlights: - **Brazil**: Exotic patterns, higher price points - **India**: Cost-effective, consistent quality - **China**: Volume production, variable quality - **Italy/Spain**: Premium grades, limited availability

Quartzite: Maximum Durability

Best Applications

- High-traffic commercial floors - Kitchen countertops (heavy use) - Outdoor paving - Pool surrounds - Fireplace surrounds

Technical Specifications

Quartzite is metamorphic sandstone, composed almost entirely of quartz. With hardness of 7-8 Mohs, it rivals engineered stone for scratch resistance while maintaining natural aesthetics.

Key properties per ASTM C616: - Absorption: Max 0.20% - Compressive strength: Min 69 MPa (typically 150-300 MPa) - Flexural strength: Min 6.9 MPa

Important Distinction

True quartzite is often confused with "soft quartzite" (actually marble or dolomite). Verify authenticity through: - Acid test (true quartzite won't etch) - Hardness test (should scratch glass) - Supplier certification

Color and Veining

Quartzite offers excellent color consistency (ΔE 1.0-2.5) with dramatic veining patterns. Popular varieties include: - Taj Mahal (warm whites) - Sea Pearl (blues/greens) - Macaubas (whites with movement)

Specification Recommendations by Project Type

Luxury Residential

**Primary**: Marble for statement areas **Secondary**: Quartzite for kitchens/high-traffic **Rationale**: Aesthetic priority with practical durability where needed

Commercial Office

**Primary**: Granite for lobbies and common areas **Secondary**: Quartzite for executive spaces **Rationale**: Balance durability with premium appearance

Hospitality

**Primary**: Granite for high-traffic zones **Secondary**: Marble for luxury suites **Rationale**: Maintenance efficiency with selective luxury

Healthcare

**Primary**: Granite or quartzite only **Avoid**: Marble (porosity concerns) **Rationale**: Infection control and durability requirements

Procurement Best Practices

1. Specify Delta-E Tolerances

Include maximum acceptable color variance in specifications: - Critical match: ΔE < 1.0 - Close match: ΔE < 2.0 - Standard: ΔE < 3.5

2. Require Digital Documentation

Modern quarries can provide: - LiDAR-verified dimensions - Spectral color profiles - Origin certification - Chain of custody documentation

3. Plan for Attrition

Order 15-20% overage for: - Fabrication waste - Future repairs - Color matching reserves

4. Verify Authenticity

Request third-party testing for: - Petrographic analysis - Mechanical properties - Absorption characteristics