Sahara Purple Andesite – Technical and Aesthetic Overview

Quarried in Tiantai County, Shaoxing, Zhejiang Province, China

General Description

Sahara Purple Andesite is a fine to medium-grained, typically aphanitic volcanic stone with occasional porphyritic textures (larger crystals like feldspar or amphibole embedded in a finer-grained groundmass), especially when formed at greater depths with slower cooling. This andesite is characterized by a distinctive, earthy-toned color palette blending:

• Smoky purple
• Pale rose
• Earthy gray

Its natural color variation and consistent textural flow make it suitable for both contemporary and traditional architecture, especially in cladding, paving, and landscaping applications.

Appearance 

• Color : Smoky purples, pale rose pinks, and earthy warm grays
• Texture : Mostly aphanitic (fine-grained), may feature porphyritic inclusions
• Pattern : Subtle and cloudy natural textures with no pronounced veining or contrast
• Grain : Fine to medium
• Natural Surface : Slightly rough or rugged depending on the cut – ideal for slip resistance

Physical and Mechanical Properties

(Typical tested results, may vary slightly per batch/quarry section)

• Density : ~2.65 – 2.78 g/cm³
• Water Absorption : ~0.45 – 0.80% by weight
• Porosity : ~0.6 – 1.2%
• Compressive Strength : 150 – 210 MPa
• Flexural Strength : 12 – 18 MPa
• Abrasion Resistance : ≤ 18 mm (high resistance)
• Mohs Hardness : ~6 – 7
• Slip Resistance (Natural) : ≥ 60 BPN (Dry); ≥ 35 BPN (Wet)

Chemical Composition (% by weight)

(Typical for andesite from the region)

• SiO₂ (Silicon Dioxide) : 55 – 63%
• Al₂O₃ (Aluminum Oxide) : 15 – 18%
• Fe₂O₃ (Iron Oxide) : 4 – 6%
• CaO (Calcium Oxide) : 5 – 7%
• MgO (Magnesium Oxide) : 1 – 3%
• Na₂O + K₂O (Alkali Oxides) : 3 – 6%
• TiO₂ (Titanium Dioxide) : ~1%
• Loss on Ignition (LOI) : <1%

Mineral Composition

• Plagioclase : 40 – 60%
• Amphibole (hornblende) : 10 – 20%
• Pyroxene : 10 – 15%
• Biotite : 5 – 10%
• Quartz (trace) : 2 – 5%
• Opaque minerals : <2%

Available Finishes

• Natural Split : Rugged, ideal for exterior wall cladding
• Honed : Smooth, matte; suitable for interior floors
• Polished : Rare; highlights color but may reduce slip resistance
• Flamed : Thermal finish, rough anti-slip surface
• Bush-hammered : Pitted surface for high grip areas
• Sandblasted : Subtle texture, soft color tone
• Brushed : Aged, soft-to-touch surface
• Tumbled : Weathered look for rustic projects

Standard Cutting Sizes (cm)

Tiles:

• 30 × 30
• 30 × 60
• 40 × 40
• 60 × 60
• 60 × 120

Custom paving:

• 20 × 10, 10 × 10, 40 × 80, etc.

Slabs:

• 2cm and 3cm thickness, up to 240 × 120 cm (for premium selections)

Cubes/Curb/Steps:

• Custom dimensions per design needs

Applications

• Exterior wall cladding (natural, flamed)
• Paving (driveways, plazas, walkways)
• Landscaping (stepping stones, edging, fountains)
• Architectural elements (columns, benches, coping)
• Facade systems
• Interior flooring (honed, brushed)

Maintenance

Low maintenance, naturally dense and less porous than many other volcanic rocks. Recommended sealing for polished or honed interior surfaces. Periodic cleaning with pH-neutral cleaner. High slip resistance surfaces need only pressure washing in exterior uses.

Summary

Sahara Purple Andesite offers a harmonious blend of natural color tones, durability, and versatility. Its technical strength and variety of finishes make it highly adaptable to both public urban applications and luxury residential or resort projects, particularly those requiring understated elegance with strong technical performance.