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How to Identify Whether Jewelry is Genuine 925 Silver or Brass

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How to Identify Whether Jewelry is Genuine 925 Silver or Brass

Zavedení

When purchasing jewelry, distinguishing between genuine 925 Sterling Silver a mosaz (a copper-zinc alloy) is crucial for ensuring value, durability, and hypoallergenic safety. Many inexpensive jewelry pieces are plated or falsely labeled, making it difficult for buyers to verify authenticity.

This comprehensive guide explores multiple testing methods, from simple at-home techniques na professional verification tools, helping you confidently identify real 925 silver vs. mosaz.

1. Understanding 925 Silver vs. Mosaz

1.1. What is 925 Sterling Silver?

  • Composition: 92.5% Čisté stříbro + 7.5% copper (for durability).

  • Properties:

    • Hypoalergenní (safe for sensitive skin).

    • Naturally tarnishes (develops a patina over time).

    • Non-magnetic.

  • Hallmark: Usually stamped “925,” “Ster,” nebo “Sterling.”

1.2. What is Brass?

  • Composition: ~67% copper + 33% zinek (may contain lead or nickel).

  • Properties:

    • Heavier and harder than silver.

    • Prone to greenish tarnish (due to copper oxidation).

    • Often gold-like in appearance (used as a cheap alternative).

  • Hallmark: Rarely stamped; may be labeled “Mosaz” nebo “Cz” (for fake gemstones).

2. Visual and Physical Inspection Methods

2.1. Check for Hallmarks

  • 925 Stříbro: Look for stamps like:

    • “925” (most common).

    • “Sterling,” “Ster,” nebo “.925.”

  • Mosaz: Typically unmarked or may have “Mosaz,” “GF” (gold-filled), nebo “Cz” (for fake stones).

⚠️ Warning: Some counterfeit jewelry has fake stamps—always verify further.

2.2. Observe the Color and Shine

  • 925 Stříbro:

    • Jasný, white-metallic luster.

    • Develops a darker patina over time (can be polished back).

  • Mosaz:

    • Yellowish-gold hue (unless plated).

    • Turns darker green/black when oxidized.

2.3. Weight and Density Test

  • Silver is lighter than brass.

  • Compare similar-sized pieces:

    • A sterling silver ring will feel lighter than a brass one.

2.4. Magnet Test (Quick Check)

  • 925 Stříbro: Non-magnetic (won’t stick to a magnet).

  • Mosaz: Usually non-magnetic, but some alloys may have slight attraction.

⚠️ Note: Some fake silver is made with non-magnetic metals, so this test alone isn’t foolproof.

3. Chemical and Scratch Tests

3.1. Nitric Acid Test (Professional Method)

  • How it Works:

    • Apply a drop of nitric acid to an inconspicuous area.

    • 925 Stříbro: Turns creamy white.

    • Mosaz: Turns green (due to copper reaction).

⚠️ Caution: Nitric acid is corrosive—wear gloves and test in a ventilated area.

3.2. Bleach Test (Home Method)

  • Procedure:

    • Place a drop of household bleach on the jewelry.

    • 925 Stříbro: Will tarnish černý within seconds.

    • Mosaz: May turn greenish or show no reaction.

3.3. Ice Melting Test (Thermal Conductivity)

  • Silver conducts heat extremely well.

  • Test:

    • Place an ice cube on the metal.

    • 925 Stříbro: Ice melts very quickly.

    • Mosaz: Ice melts slowly.

4. Professional Verification Tools

4.1. XRF (X-Ray Fluorescence) Testing

  • Used by jewelers to detect exact metal composition.

  • Accurate but expensive (not practical for home use).

4.2. Electronic Silver Testers

  • Measures electrical conductivity:

    • 925 Stříbro has a unique resistance reading.

    • Mosaz gives a different result.

4.3. Density Measurement (Archimedes’ Method)

  • Formula: Density = Mass / Volume

  • 925 Stříbro: ~10.49 g/cm³

  • Mosaz: ~8.4–8.7 g/cm³

5. Common Fake Silver Plating Tricks

Many cheap jewelry items are brass coated with silver plating. To detect:

5.1. Rub Test (Wear-Off Check)

  • Use a soft white cloth to rub the jewelry firmly.

  • If black/green residue appears, it’s likely brass underneath.

5.2. Scratch Test (Caution: Damaging)

  • Lightly scratch an inconspicuous area with a needle.

    • 925 Stříbro: Scratch shows same color (solid silver).

    • Plated Brass: Reveals a yellowish layer underneath.

5.3. Smell Test

  • 925 Stříbro: Odorless.

  • Mosaz: May have a metallic or coppery smell.

6. Where to Buy Authentic 925 Stříbro?

To avoid fakes:
✔ Reputable jewelers (check reviews).
✔ Certified sellers (look for RJC or ISO certifications).
✔ Avoid too-good-to-be-true deals (extremely low prices = likely fake).

Závěr

Distinguishing real 925 silver from brass requires a mix of:
✅ Visual checks (hallmarks, color).
✅ Physical tests (weight, magnetism).
✅ Chemical reactions (nitric acid, bleach).
✅ Professional tools (XRF, electronic testers).

By following these methods, you can confidently verify jewelry authenticity and avoid scams.