How Does Purity (Karat vs 950) Affect Jewellery Strength

Purity in jewellery refers to how much of the piece is the pure precious metal (gold or platinum) and how much is alloyed with other metals. The metric for gold is “karat” (e.g., 14K, 18K) and for fine metals like platinum often “950” (meaning 95% pure) or other fineness marks. The purity influences properties like hardness, wear-resistance, colour, cost and durability.

Gold – Karat system

• 24 K gold = (ideally) 100% gold (although commercially more like >99.9%). Pure gold is very soft and malleable, therefore not ideal for long-wear rings without reinforcement.
• 18 K gold = 75% gold + 25% alloy metals. This retains much of the gold’s colour richness, while improving strength relative to 24K.
• 14 K gold = 58.3% gold + 41.7% other metals; stronger and more suitable for daily-wear rings in many cases.
• Lower karat means more alloy metals → usually higher strength/harder metal, but also slightly different colour and potentially more base metal exposure (which may affect wear, colour or allergies).

Platinum – 950 and similar fineness marks

• Jewellery-grade platinum is often stamped “950PT” or simply “950” meaning about 95% platinum and 5% other metals.
• Because platinum is naturally strong and dense, even at high purity it retains structural integrity; the high purity also contributes to its hypoallergenic properties and long-term durability.
• The small % of alloyed metal allows the platinum to be workable (for casting, forging) while retaining its strength.

Effect on strength and wear

• Generally: more alloyed metal = harder/stronger metal but possibly more colour/alloy compromise; higher purity = more precious metal content, more lustre and value, but may be softer (in the case of gold) or heavier/more expensive.
• For gold: a 24K gold ring would be very soft and likely prone to deformation, thinning and scratching if worn daily. Lower karat gold (14K/18K) provides a better balance for everyday rings.
• For platinum: because the base metal is inherently strong, a 950 platinum ring offers excellent durability and minimal loss of metal over time — the purity level is high without compromising strength.
• In practice: make sure the ring design (especially shank thickness, prong strength, gemstone setting) is appropriate for wear-intensity; purity is one factor but design and use matter too.

For daily wear, one should favour metal alloys that balance purity and strength: e.g., 14K or 18K gold rather than 24K, and high-purity platinum (950) rather than lower-grade. The purity mark is a useful guide but not the only determinant of durability — the alloy composition, design execution and finish also matter.