Does 18K Gold Stretch? Necklace Thinning Explained

Question
dear sir i was given a 18k gold necklace with a 18k crusifix when i was 17 years old,i have worn it everyday now at age 47,30 years,at one time it would not go over my head,now it does,it seems much thinner than before.does 18k necklaces stretch and after all this time will it get thinner it is also italian gold UNO-A-ERRE is name of maker.thanks for your time Larry

Answer
Larry
18kt is much softer than 14kt or 10 since it has more pure gold approx. 75% pure as opposed to 58.3% on 14kt.
Gold is very soft and it does stretch of course. So the answer is Yes it did stretch and eventually the weakest link will break take it to a local jeweler and have it checked.
all the best
Les