PD on a hoop typically represents palladium. Your ring could be palladium-plated if it's PD published around it. HK is really a trademark that stands for Harriet Kelsall. They layout and provide jewellery everywhere in the British isles also to other places also.  Region hallmarks: Some countries have their unique hallmarking https://slot-habanero75431.mpeblog.com/65299712/an-unbiased-view-of-jp88