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Metamorphic

Onyx — a natural stone guide for buyers, designers, and contractors.

Onyx is a metamorphic stone sourced primarily from Turkey, Iran & Pakistan. With a Mohs hardness of 3 and water absorption of 0.15%, it is commonly used for Backlit walls, vanities, feature walls.

3Mohs hardness
0.15%Water absorption
PoorFreeze-thaw
$25–80 / sq ftTypical cost range
Technical Specifications

By the numbers

Mohs hardness 3
Water absorption 0.15%
Freeze-thaw Poor — interior only
Density 2.72 g/cm³
Applications Backlit walls, vanities, feature walls
Cost range $25–80 / sq ft
Finishes Available

Surface options

Honed

Matte, flat surface. Most common for interior flooring and walls.

Polished

High gloss finish. Maximizes color and pattern depth.

Brushed/Flamed

Textured surface for exterior use and slip resistance.

Evaluation

Pros & cons

Advantages

  • ✓ Natural, one-of-a-kind appearance
  • ✓ Origin: Turkey, Iran & Pakistan
  • ✓ Freeze-thaw performance: Poor — interior only
  • ✓ Cost range: $25–80 / sq ft
  • ✓ Suitable for: Backlit walls, vanities, feature walls

Considerations

  • – Requires sealing and regular maintenance
  • – Heavier and more expensive to install than synthetic alternatives
  • – Color/pattern variation between batches
Frequently Asked Questions

Onyx — common questions

Onyx is commonly used for Backlit walls, vanities, feature walls. Its Mohs hardness of 3 and Poor — interior only freeze-thaw rating determine where it performs best.
Onyx has a Mohs hardness of 3. For reference, granite is Mohs 6–7, marble is Mohs 3–4. Higher hardness means better scratch and wear resistance.
Onyx has a water absorption of 0.15%. Stones with higher absorption benefit most from a penetrating sealer applied annually. Always test with the water-drop test: if water absorbs in under 4 minutes, reseal.
Onyx typically costs $25–80 / sq ft per square foot for the material. Installation adds $8–$20/sq ft depending on complexity and region. Request current pricing from SmartStones verified suppliers.
Onyx is rated "Poor — interior only" for freeze-thaw performance. Its water absorption is 0.15%. Lower water absorption = better freeze-thaw resistance. For northern climates, verify the stone meets your project's freeze-thaw requirements.
Care Guide

How to Care for Onyx

Essential maintenance steps to keep Onyx surfaces looking their best for decades.

1

Daily cleaning

Wipe with a damp microfiber cloth. Use a pH-neutral stone soap for weekly cleaning. Avoid vinegar, bleach, or multi-surface cleaners.

2

Blot spills immediately

Blot (do not wipe) any spills to prevent staining or etching. Rinse with water and dry.

3

Annual sealing

Apply a penetrating impregnator sealer to dry, clean Onyx. Allow 10–15 minutes of dwell time, wipe excess, and cure for 24 hours. Re-seal when the water-drop test fails.

4

Professional restoration

If the surface develops deep scratches, chips, or loses its finish, contact a stone restoration professional. Most damage can be corrected by re-honing or re-polishing.

Compare

How Onyx compares

Applications

Where Onyx excels

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Pricing

Onyx price guide

Typical material cost
$25–80 / sq ft / sq ft

The full Onyx price guide covers material vs. installed costs, regional pricing across all 6 US regions and Canada, format-specific breakdowns, and the top cost drivers for your project.

Full Onyx price guide →

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