Wow thanks Vienna- that explains it.
My Solid coffee bean earings were made out of my old scrap gold which was a mixture of 9ct and 14 ct. so was the matching pendant but was a different batch. The flux was only a problem with the earings, which were plated in the end, but the pendant was just perfect. My white gold earings and pendant, cast using the same mould, must have been rhodium plated after as with all white gold jewelery. No flux problems with that either.
For any of you who have bits of gold jewelery lying around that you never wear, and have coveted something solid that is hard to find or very expensive, it is well worth asking a proper jeweler to melt the gold and make it for you. I paid about £360 for the labour but received 2 solid pendants and 2 matching sets of earings for that price. It was about 3 or 4 years ago now, so may cost more. I wear the pendant and always fiddle with it and it is my favourite piece by far. It is not hallmarked though, although I am sure this could have been done at a price, but I knew where the gold had come from.