What Is a Watch Crystal?
The crystal is the transparent cover that sits over the dial. In common usage it’s called the ‘glass’, though only mineral and sapphire crystals are actually glass, acrylic is a plastic. The crystal is held in place by the bezel or pressed into a groove in the case, and it forms part of the water-resistance seal. A cracked or chipped crystal breaks that seal immediately.
The Three Crystal Materials Compared
| Property | Acrylic | Mineral Glass | Sapphire Crystal |
|---|---|---|---|
| Scratch resistance (Mohs) | ~3 | ~5–6 | ~9 |
| Shatter resistance | High (flexible) | Moderate | Low (brittle on impact) |
| Polishable by watchmaker | Yes | No | No |
| Optical clarity | Good (slight distortion) | Very good | Excellent |
| Cost to replace | Low | Moderate | High |
| Common on | Vintage, entry-level, field watches | Mid-range, everyday | Luxury, tool, dive watches |
The Three Crystal Types
Acrylic (Plastic / Hesalite)
Mohs ~3. Acrylic scratches easily, even fingernails can mark it, but this is its strength: scratches can be polished out by a watchmaker, restoring near-perfect clarity. Acrylic is also flexible, so it bends rather than shatters on impact. The original Omega Speedmaster Moonwatch used Hesalite acrylic; it was chosen for space use partly because shattered sapphire inside a spacesuit is dangerous.
Mineral Glass
Mohs ~5–6. Mineral glass is the most common crystal type on everyday mid-range watches. It handles light scratches from daily wear much better than acrylic, but it cannot be polished, once scratched, it stays scratched. It’s also more brittle than acrylic; a hard impact can crack or shatter it.
Sapphire Crystal
Mohs ~9. Synthetic sapphire (aluminium oxide) is second only to diamond in hardness and virtually scratch-proof in normal use. It offers exceptional optical clarity. It’s expensive to produce and significantly more brittle than the other materials, hard concentrated impacts can crack it despite its surface hardness. Standard on luxury watches from Rolex, IWC, and Omega.
How to tell which crystal your watch has: Price is the easiest indicator. Watches under approximately €100–150 almost always use mineral or acrylic. Sapphire does become more common as the price climbs, but the rule is weaker than it looks: our own Swiss-made Romanson has a sapphire crystal at €74, and every Hislon has one from €149, starting with the Women Classic Queen. You can also tap the crystal lightly with a fingernail: acrylic sounds dull and plastic-like; mineral and sapphire sound crisper. Anti-reflective coating is applied almost exclusively to sapphire.
Sapphire crystal is scratch-resistant, not shatter-proof. The same hardness that resists surface scratches makes it brittle under concentrated impact. Dropping a watch with a sapphire crystal face-down onto concrete or tile can crack or shatter it completely, a repair that costs considerably more than replacing mineral glass. Don’t assume ‘sapphire’ means indestructible.
Don’t replace a scratched acrylic crystal yet. A watchmaker can polish acrylic back to near-new clarity in a few minutes using a buffing compound. It costs a fraction of a replacement and the result is often indistinguishable from new. Bring it in before spending money on a new crystal.
What to Do If Your Crystal Is Cracked or Scratched
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1Assess the severity, fine surface scratches on acrylic are polishable; deep gouges, cracks, or chips on any material mean the crystal should be replaced. Run your fingernail across the scratch: if it catches, it’s too deep to polish.
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2Protect against water immediately, any crack or chip, no matter how small, breaks the water-resistance seal. Until the crystal is replaced, keep the watch away from water entirely: no handwashing, no rain, no shower.
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3Bring it to a watchmaker, crystal replacement requires the correct diameter, curvature (flat, domed, or double-domed), and thickness for your specific case. A generic fit risks an incomplete seal and future water damage.
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4Discuss the material with your watchmaker, we typically match the original material. However, if your vintage watch has an acrylic crystal and you prefer sapphire, or if you want to restore an original acrylic, we can discuss what’s right for your watch.
How Much Does Crystal Replacement Cost?
Crystal replacement at Iglisi Watch is priced based on the crystal type and the difficulty of fitting it to the specific case. Approximate ranges:
| Crystal Type | Relative cost | Notes |
|---|---|---|
| Acrylic | Lowest | Many vintage sizes in stock; very fast fitting |
| Mineral glass | Middle | Most common; we stock common diameters |
| Sapphire crystal | Highest | Sourced to order; price depends on diameter and shape |
| Hesalite (Omega Speedmaster) | Quoted individually | Proprietary; sourced from specialist suppliers |
If we do not have the specific crystal in stock, we source it and typically have it within 3–5 days for mineral and common sapphire sizes. Unusual shapes (tonneau, cushion, asymmetric) take longer. We give you a price before ordering.
Polishing Acrylic Crystals
Acrylic is the only crystal material that can be polished to remove scratches. If the acrylic is scratched but not cracked, a watchmaker can resurface it using a succession of progressively finer abrasive compounds, returning the crystal to near-optically-clear condition. This is significantly cheaper than replacement and in some cases produces a better result than fitting a new acrylic, since the original may be a specific size or curvature no longer stocked.
Surface scratches - from keys, bags, normal contact - polish out completely if they do not penetrate too deep. Deep gouges that catch a fingernail may require replacement rather than polishing. Bring the watch in and we will assess it and tell you which approach makes more sense.
Mineral glass and sapphire cannot be polished by a watchmaker. Scratches in mineral glass are permanent; a scratched mineral crystal must be replaced. Sapphire is similar - only specialist industrial polishing equipment can address sapphire scratches, and at that cost it is always more economical to replace the crystal.
Protecting Your Crystal
The most common sources of crystal damage are: hard surface impacts (setting a watch face-down on a stone or glass surface), contact with other metal objects in a pocket or bag, and wear from abrasive materials (concrete, brick, rough metal edges). A few practical habits reduce risk significantly:
- Store watches individually or in a watch roll when not worn. Storing multiple watches together causes metal-on-crystal contact.
- Place watches face-up on soft surfaces. A mineral crystal set face-down on a hard surface will scratch; sapphire is more resistant but not immune to impact chips.
- Do not wear a watch when doing work that involves coarse abrasives or heavy impacts (masonry, heavy construction). No crystal is impervious at that level.
- If the watch is stored long-term, the crystal condition should be checked before regular use. A hairline crack in an otherwise-working watch will eventually allow moisture into the case.
Frequently Asked Questions
What is the difference between acrylic, mineral, and sapphire watch crystals?
Acrylic (plastic) scratches easily but can be polished by a watchmaker and rarely shatters. Mineral glass is more scratch-resistant but can't be polished and breaks under hard impact. Sapphire crystal is nearly scratch-proof but brittle - it can crack under concentrated impact despite its hardness. Each has genuine advantages depending on the watch's purpose and price point.
Can a scratched watch crystal be repaired?
It depends on the material. Acrylic crystals can be polished back to near-new clarity by a watchmaker using buffing compound - this is cost-effective and often looks like new. Mineral and sapphire crystals cannot be polished; they must be replaced. Replacement cost depends on the watch, the crystal shape, and the material.
How urgent is it to replace a cracked watch crystal?
Very urgent if water resistance matters to you. A cracked or chipped crystal breaks the water-resistance seal immediately. Even 'water resistant' watches will allow moisture ingress through a damaged crystal. Bring the watch in before wearing it near water.
How much does watch crystal replacement cost?
The price depends on the material, the diameter and the shape, so we quote it at the counter rather than from a list. Acrylic is the cheapest to replace, mineral glass sits in the middle, and sapphire costs the most because it is sourced to order. We provide a quote before ordering any crystal not in stock. Turnaround is same-day or next-day for common sizes.
What is the difference between mineral glass and sapphire crystal?
Mineral glass is hardened silicate glass (Mohs ~5–6), scratch-resistant for everyday use but not immune to harder materials. Sapphire crystal is synthetic corundum (Mohs ~9), highly scratch-resistant but more brittle on hard impact. Sapphire is significantly more expensive to replace. For most everyday watches, mineral glass is sufficient.
How do I know if my watch crystal needs replacing?
Replace the crystal if it is cracked (a cracked crystal breaks the water-resistance seal immediately), if scratches distort visibility of the dial, or if a chip on the edge is progressing. Surface scratches on an acrylic crystal can be polished rather than replaced. Bring the watch in for an assessment - we will tell you which approach makes sense for the specific damage.
Crystal Cracked or Scratched? We Can Help.
Walk into our workshop in Durrës. We carry replacement crystals for a wide range of watches, can polish acrylic crystals while you wait, and will advise on the best replacement material for your specific piece. No appointment needed.
Rruga Aleksander Goga · Durrës 2001 · Albania · +355 67 571 6090
We also sell watches. Brand-new men’s and women’s watches from €50, each with a 1-year guarantee. Order on WhatsApp with cash on delivery anywhere in Albania, or try them on at the workshop in Durrës. See what you get at each price.
Published by Iglisi Watch · Durrës, Albania · May 2026. Crystal replacement availability depends on case specifications.