Complete Guide to Gold Purity Standards: Understanding 24K, 22K, 18K & Fineness
Understanding Karats vs. Millesimal Fineness
Gold purity is commonly expressed either in karats (out of 24 parts) or millesimal fineness (parts per thousand). For example, 24K corresponds to 999 fineness, 22K to 916 fineness, and 18K to 750 fineness.
Computerized touch testing (XRF) and fire assay cupellation determine these exact proportions with scientific precision, eliminating guesswork and estimation errors.
- 24 Karat (999 fineness) - 99.9% pure gold, primarily used for bullion bars and investment coins
- 22 Karat (916 fineness) - 91.6% pure gold alloyed with copper/silver, ideal for traditional fine jewellery
- 18 Karat (750 fineness) - 75.0% pure gold, preferred for studded diamond and gemstone jewellery
Why Independent Assaying Verification Matters
Alloy inconsistencies and surface treatments can disguise lower karatage. Third-party metallurgical assaying ensures complete traceability, verifying that what is stamped matches the true core metal composition.
How Rajendra Touch Lab Delivers Purity Certainty
From instant non-destructive XRF spectrometry to fire assay cupellation and precision weight documentation, our laboratory at Ahilyabai Chowk, Kalyan (W) provides certified, bank-recognized purity analysis with quick turnaround.
Essential Rules of Thumb
- Always verify standard fineness markings: 999 (24K), 916 (22K), and 750 (18K).
- Independent lab assay reports protect you from paying 22K prices for substandard alloy mixtures.
- Always demand a certified purity test before buying, selling, or pledging gold collateral.
Visit Rajendra Touch Lab in Kalyan (W)
Prakash Tower, Shop 11/A, Opp. Raja Hotel, Ahilyabai Chowk, Kalyan (W)
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