You just need to be a wee bit careful regarding the sale of unhallmarked items in the UK.
If you have described your ring as being made of gold, then with one or two minor exceptions it MUST be hallmarked otherwise you're actually breaking the law.
I would apologise to the buyer and get the ring back. Then you've got a couple of options. you could either tell the buyer that you'll get the ring hallmarked and sell it back to him, or you could keep it, or you could offer it for resale without describing it as being made of gold.
Pop it in to your local independent jeweller who can arrange to have it hallmarked, or contact one of the main assay offices for advise, if you wish to have it properly marked.
www.assayofficelondon.co.uk would be a good start.
Rating
Unmarked Gold by: Anonymous
If you are buying unmarked gold or gold colored jewelry with uncertain or "iffy" marks, make sure you get an unconditional money back guarantee from the seller as to gold carat or the piece. Then have it checked.
Rating
SOLID GOLD? by: Anonymous
Hi Heather - don't stress. It's either 9ct gold or it isn't. Apologize to the buyer for the confusion. Ask if buyer would return the ring. Refund the buyer. Take the ring to a reputable jeweler and ask to have it TESTED. You do not want an opinion. Gold plating often looks like solid gold.
The numbers you mention are not the common marks you see for caratage.
