PD on a hoop ordinarily represents palladium. Your ring may very well be palladium-plated if it has PD published above it. HK is a trademark that stands for Harriet Kelsall. They design and supply jewellery everywhere in the UK and also to other places too.  The Sunshine refers back to https://emilioaluck.frewwebs.com/37506853/the-definitive-guide-to-jp88