They look similar in photos. They do not feel similar on the hand.
Weight and feel
Platinum (PT950) is denser. A 2.5mm band in platinum feels noticeably heavier than the same band in 18K. Some clients love that; others find it tiring on a thin finger.
Color and aging
18K yellow gold stays yellow. White gold is rhodium-plated and will need a re-plate every 18–24 months to stay bright white. Platinum does not plate — it patinas to a soft matte, which most owners prefer over time.
Scratches
Both scratch. Platinum scratches more visibly because it is softer (95 vs 120–200 VHN), but the scratch moves metal rather than removing it. Gold removes metal. Over 20 years, a platinum ring wears less than an 18K one.
Price
Platinum is roughly 1.5–2x the material cost of 18K for the same ring. Budget for that if you love the weight.
