Gold Purity: Karat System, Fineness Scale, Alloy Composition & Hallmarking
Gold purity defines the ratio of pure gold (Au) to total metal mass in an alloy. Pure gold has an atomic number of 79, a density of 19.32 g/cm³, and a melting point of 1,064 °C. Two standardized measurement systems quantify gold purity worldwide: the karat system and the millesimal fineness scale. Malaysia's gold market uses both systems, with 916 (22K) dominating jewellery and 999 (24K) dominating investment products.
Gold Purity Measurement Systems
The karat system divides gold content into 24 equal parts. 24 karat (24K) equals 100% gold. 18 karat (18K) equals 18/24 = 75% gold. The word "karat" derives from the Greek keration (carob seed), a historical unit of mass equal to 189–205 mg.
The millesimal fineness system expresses gold content as parts per thousand by mass. A fineness of 999.9 indicates 99.99% gold. A fineness of 916 indicates 91.6% gold. The International Organization for Standardization (ISO 9202:2014) defines the standard fineness grades for precious metals.
Karat-to-Fineness Conversion Formula
Fineness = (Karat ÷ 24) × 1000. Karat = (Fineness ÷ 1000) × 24. These two formulas convert between the systems without rounding loss.
Gold Purity Grades: Karat, Fineness & Gold Content
| Karat | Fineness | Gold % | Alloy % | Common Name |
|---|---|---|---|---|
| 24K | 999.9 | 99.99% | 0.01% | Four-nine fine gold |
| 24K | 999 | 99.9% | 0.1% | Three-nine fine / Fine gold |
| 22K | 916 | 91.6% | 8.4% | 916 gold (Malaysia standard) |
| 21K | 875 | 87.5% | 12.5% | Gulf standard |
| 18K | 750 | 75.0% | 25.0% | 750 gold |
| 14K | 585 | 58.5% | 41.5% | 585 gold |
| 10K | 417 | 41.7% | 58.3% | Minimum legal gold (USA) |
| 9K | 375 | 37.5% | 62.5% | 375 gold (UK/Australia) |
Gold Alloy Composition by Colour
Alloying metals determine the colour, hardness, and corrosion resistance of gold. The table below lists standard alloy compositions for 18K (750 fineness) gold, the grade that produces the widest colour range.
| Colour | Au % | Ag % | Cu % | Pd % | Zn % |
|---|---|---|---|---|---|
| Yellow (18K) | 75.0 | 12.5 | 12.5 | — | — |
| Rose / Pink (18K) | 75.0 | 2.75 | 22.25 | — | — |
| Red (18K) | 75.0 | — | 25.0 | — | — |
| White – Pd (18K) | 75.0 | — | — | 25.0 | — |
| White – Ni (18K) | 75.0 | — | 5.0 | — | 20.0* |
| Green (18K) | 75.0 | 25.0 | — | — | — |
*White–Ni alloy: 20% column represents combined Ni + Zn. Typical ratio is 15% Ni, 5% Zn. EU Nickel Directive (94/27/EC) restricts nickel in items with prolonged skin contact to <0.5 μg/cm²/week release rate.
Gold Alloy Vickers Hardness Comparison
Vickers hardness (HV) measures indentation resistance under a diamond pyramid load. Higher HV values indicate greater scratch and deformation resistance. The values below represent annealed (soft) and work-hardened states.
| Alloy | Fineness | HV (Annealed) | HV (Work-Hardened) | Suitability |
|---|---|---|---|---|
| Pure gold (24K) | 999 | 25 | 60–70 | Investment bars, coins |
| 22K yellow | 916 | 45–65 | 100–120 | Traditional jewellery |
| 18K yellow | 750 | 120–160 | 170–230 | Daily-wear jewellery |
| 18K white (Pd) | 750 | 130–150 | 200–250 | Gemstone settings |
| 18K rose | 750 | 140–170 | 190–240 | Fashion jewellery |
| 14K yellow | 585 | 150–180 | 220–260 | High-wear items, clasps |
| 9K yellow | 375 | 170–200 | 250–290 | Budget jewellery |
Pure gold at 25 HV (annealed) deforms under fingernail pressure. 916 gold at 45–65 HV resists casual scratching. 750 gold at 120–160 HV holds gemstone prongs securely. Each halving of gold content approximately doubles Vickers hardness.
Gold Purity Pricing Mechanics in Malaysia
Gold price per gram scales linearly with purity. The live gold price tracker displays the 999 (24K) spot price. Multiply that price by the purity fraction to derive the base metal value for any karat.
| Karat | Multiplier | Price if 999 = RM400/g | Price if 999 = RM450/g |
|---|---|---|---|
| 24K (999) | × 1.000 | RM400.00 | RM450.00 |
| 22K (916) | × 0.916 | RM366.40 | RM412.20 |
| 18K (750) | × 0.750 | RM300.00 | RM337.50 |
| 14K (585) | × 0.585 | RM234.00 | RM263.25 |
| 9K (375) | × 0.375 | RM150.00 | RM168.75 |
Jewellery retail prices add making charges (upah) of 8–30% above metal value. Investment-grade bars carry premiums of 2–5% above spot. When selling gold back to dealers, the buyback price deducts a spread of 1–5% from spot value. Making charges are not recoverable at resale. The gold calculator computes exact metal value by weight and purity.
Gold Hallmarking Standards and Verification Methods
A hallmark is a stamped or laser-engraved mark on a gold item that certifies its purity. Malaysia does not have a mandatory government hallmarking scheme as of 2026. The Ministry of Domestic Trade and Consumer Affairs (KPDNHEP) enforces the Trade Descriptions (Certification and Marking of Gold and Gold Alloy Articles) Order 2011, which requires gold articles sold as a specific karat to match that stated purity.
Hallmark Stamp Formats
- 916 — stamped on 22K gold jewellery sold in Malaysia
- 750 — stamped on 18K items
- 999 or 999.9 — stamped on investment bars and coins
- Assay office marks — UK items carry town marks (e.g., leopard head for London). Swiss items carry the St. Bernard dog head for 750+ fineness.
- LBMA stamp — London Bullion Market Association accreditation on Good Delivery bars (minimum 995 fineness, 350–430 troy oz per bar)
Gold Purity Testing Methods
| Method | Accuracy | Destructive | Cost | Notes |
|---|---|---|---|---|
| Touchstone (streak test) | ±5% | Minimally (surface scratch) | Low | Compares streak colour to reference strips |
| Acid test (nitric/aqua regia) | ±1–2% | Yes (small sample) | Low | Nitric acid dissolves base metals; gold resists |
| Electronic conductivity tester | ±1–3% | No | Medium | Measures electrical resistance; affected by plating |
| Specific gravity (hydrostatic) | ±1% | No | Low | Pure gold density = 19.32 g/cm³; hollow items skew results |
| X-ray fluorescence (XRF) | ±0.1–0.5% | No | High | Industry standard; reads surface to ~20 μm depth |
| Fire assay (cupellation) | ±0.01% | Yes (sample melted) | High | Definitive method for LBMA and refinery certification |
| ICP-OES spectrometry | ±0.01% | Yes (sample dissolved) | High | Detects trace elements; laboratory-only method |
Gold Purity: Malaysian Cultural Preferences
Malaysia's three largest ethnic communities — Malay, Chinese, and Indian — maintain distinct gold purity traditions. These preferences influence retail demand, jewellery design, and dealer inventory across the country.
Malay Gold Purity Tradition
Malay weddings require mas kahwin (mandatory bridal gift). Kelantan, Terengganu, and Kedah set minimum mas kahwin values by state religious authority, typically denominated in gold weight. 916 gold (22K) dominates Malay bridal jewellery. Standard sets include: rantai leher (necklace), subang (earrings), gelang tangan (bracelet), and cincin (ring). Traditional Malay goldsmithing favours yellow-gold colour — achieved exclusively at 916 or higher purity. Rose gold and white gold occupy a minor share in Malay jewellery demand.
Chinese Malaysian Gold Purity Tradition
Chinese Malaysian gold purchases concentrate on 999 (24K) purity. Demand peaks during Chinese New Year, weddings (si dian jin — four items of gold from groom's family), and childbirth celebrations. 999 gold items include: bangles, pendants engraved with "Fu" (¦), coins, and baby lock pendants. Chinese-owned goldsmith shops (e.g., Poh Kong, Habib sub-brand Oro Italia) stock 999 gold prominently. Investment-grade 999.9 gold bars from PAMP, Perth Mint, and Royal Mint also carry strong Chinese Malaysian demand.
Indian Malaysian Gold Purity Tradition
Indian Malaysian jewellery purchases centre on 916 (22K) gold. Wedding jewellery (thaali, bangles, jhumka earrings, waist chains) follows South Indian temple jewellery design conventions. Deepavali, Pongal, and Akshaya Tritiya drive seasonal demand spikes. Indian goldsmiths in areas such as Little India (Brickfields, Kuala Lumpur) and Lebuh Pasar specialize in 916 gold with high-detail filigree, granulation, and kundan settings. Weight-based pricing (per gram of 916 gold plus making charges) is the standard transaction model.
Gold Purity Standards by Country
| Country / Region | Dominant Jewellery Purity | Investment Standard | Hallmarking |
|---|---|---|---|
| Malaysia | 916 (22K) | 999 / 999.9 | Voluntary (Trade Descriptions Order 2011) |
| India | 916 (22K) | 999 | BIS hallmarking mandatory since 2021 |
| UAE / Gulf States | 875 (21K) | 999.9 | Bareeq system (mandatory) |
| China | 999 (24K) | 999.9 | GB/T standard (mandatory) |
| United Kingdom | 375–750 (9K–18K) | 999.9 | Hallmarking Act 1973 (mandatory) |
| United States | 585 (14K) | 999.9 | FTC guidelines (voluntary) |
| Italy | 750 (18K) | 999.9 | Star mark (mandatory) |
Gold Purity Selection Criteria
| Purpose | Recommended Purity | Rationale |
|---|---|---|
| Long-term investment | 999 / 999.9 bars | Maximum gold content per gram; lowest dealer premiums (2–5%); highest liquidity |
| Malay wedding jewellery | 916 (22K) | Cultural standard; rich yellow colour; adequate durability for occasional wear |
| Indian wedding jewellery | 916 (22K) | Traditional purity for temple jewellery designs; weight-based pricing standard |
| Chinese New Year gifts | 999 (24K) | Cultural symbol of pure wealth; standard for coins, pendants, and bangles |
| Daily-wear rings & bracelets | 750 (18K) | HV 120–160 resists scratching; holds prong settings for diamonds and gemstones |
| White gold or rose gold items | 750 (18K) | 25% alloy fraction enables full colour range; 916 and 999 remain yellow |
| Budget jewellery | 585 (14K) or 375 (9K) | Lower gold cost per gram; highest hardness; common in Western-style designs |
Gold Purity Value Calculator
Enter gold weight and select karat grade. The calculator multiplies weight by purity fraction and live spot price to return the metal value in MYR.
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