a 24" 3mm rope necklace in 14kt gold would weigh probably about 16-17 grams.
a 24" 2.5mm rope would weigh closer to 11.5-12 grams. both are averages, of course.
for those the type of clasp could make the weight up a little (C-ring instead of lobster claw)
as long as you know the chain is hollow, and it is well made, that isn't necessarily a bad thing. i have a hollow rope necklace that i've been wearing pretty much nonstop for the last decade. i had to have a minor repair made on one of the ends where it attached to the rope, but not the rope itself.
that's pretty. and it is probably hollow, but then again, i don't think that's necessarily a bad thing. personally i'm also a big fan of 9kt and 10kt gold.
i think one of the big differences between hollow ropes and non-hollow ones (beyond the price, and weight difference) is that the hollow ones are not well suited for a heavy charm or pendant. i have a lightweight, flat charm on the one i wear and it has never been a problem and again, aside from days when i've had surgery or had it at the jeweler for repairs, i've worn this necklace for a decade, 24/7.
Once again thank you, I really appreciate your help.
So I was led to believe that the piece in question is solid so I'm really glad that you helped and gave some great advice on the difference between hollow vs solid.
sometimes people say "solid gold" and they mean that it isn't plated, or that it is real gold. not necessarily that - in the case of a rope necklace or a bangle bracelet or something - the piece itself is solid and not hollow.
like... this ring is solid gold might mean it isn't costume jewelry. but if there are stones set in it then it isn't actually solid gold, because there are stones.
in other words, the phrase "solid gold" might just be someone's casual way of saying it is karated (9k, 10k, 12k, 14k, 18k, etc) gold, and not gold-filled or gold plated. they might not have been attempting to intentionally mislead you, it might have just been unintentionally referring to the piece as being real, as opposed to costume.