| 1 | Sapphire Crystal Panels | Approximately 9 on the Mohs scale | Exceptional
Highly resistant to everyday scratching; commonly selected where optical clarity and surface hardness are priorities. | Excellent scratch resistance, high optical clarity, strong chemical resistance, and stable performance over time. | More expensive than ordinary glass; can be brittle and may chip or fracture under severe impact. | Premium watch covers, optical windows, instrument displays, camera covers, and specialized protective panels. |
| 2 | DLC-Coated Metal Components | Typically about 1,500–3,000 HV, depending on coating design and process | Exceptional
Diamond-like carbon coatings are assessed with hardness, adhesion, wear, and friction tests rather than a single universal scratch score. | Very high hardness, low friction, good wear resistance, and strong performance on moving metal parts. | Performance depends heavily on substrate preparation, coating thickness, adhesion, and operating conditions. | Gears, shafts, valves, precision tools, automotive components, and high-wear mechanical parts. |
| 3 | Technical Ceramic Surfaces | Often about 8–9 on the Mohs scale; composition varies | Very High
Dense ceramics generally resist abrasive wear and surface scratching better than common plastics and metals. | High hardness, good heat resistance, strong chemical stability, and durable appearance. | Can be brittle; edges and thin sections may chip if subjected to impact or poor handling. | Kitchen surfaces, wear plates, cutting tools, watch components, laboratory equipment, and decorative panels. |
| 4 | Hardened Aluminosilicate Glass | Usually around 6–7 on the Mohs scale | High
Ion-exchange strengthening improves damage tolerance; surface scratch resistance still depends on glass composition and finish. | Good transparency, smooth touch, broad availability, and better damage tolerance than untreated standard glass. | Not scratch-proof; sand, quartz particles, and other hard contaminants can still mark the surface. | Electronic displays, touch panels, control interfaces, appliance panels, and architectural glazing. |
| 5 | PVD Hard Coatings | Common coating hardness ranges from approximately 1,500–3,000 HV | Very High
Coating quality is commonly evaluated through adhesion, micro-abrasion, wear, and scratch testing. | Thin, durable, decorative, and suitable for improving wear resistance without substantially changing component dimensions. | Coatings can fail if adhesion is poor; sharp impacts, unsuitable substrates, or aggressive chemicals may cause damage. | Hardware, tools, molds, watches, consumer fittings, medical instruments, and industrial components. |
| 6 | Hard-Coated Polycarbonate Sheets | Varies by formulation; often rated around 3H–6H by pencil-hardness testing | Moderate to High
Commonly evaluated using ASTM D3363 or ISO 15184 pencil-hardness methods, although results are not directly equivalent to Mohs hardness. | Much better impact resistance than glass, low weight, easy fabrication, and useful optical transparency. | Still softer than glass or ceramics; hard coatings may wear through, especially under repeated abrasion. | Machine guards, safety glazing, protective covers, aircraft interiors, visors, and impact-prone transparent panels. |
| 7 | Thermoplastic Polyurethane Protective Film | Soft-to-medium surface hardness; formulation and topcoat strongly affect performance | Good for Daily Wear
Designed to absorb minor abrasion and, in some formulations, recover from light surface marks through elastomeric self-healing. | Flexible, impact-absorbing, conformable, and replaceable; suitable for curved or irregular surfaces. | Can yellow, dent, lift at edges, or show deeper cuts; it is not equivalent to a hard mineral surface. | Vehicle paint protection, device surfaces, bicycle frames, sporting equipment, and high-contact plastic parts. |
| 8 | Abrasion-Resistant Powder or Liquid Coatings | Varies widely; commonly specified by pencil hardness, abrasion loss, or coating-specific test data | Application Dependent
Taber abrasion, pencil hardness, adhesion, and chemical-resistance tests are often used to compare coating performance. | Can protect large areas, offer color and texture options, and reduce maintenance on metal or composite surfaces. | Performance depends on preparation, curing, thickness, impact resistance, and exposure to chemicals or weather. | Industrial enclosures, furniture, appliances, transport equipment, architectural metalwork, and machinery housings. |
