It's junk. The brooch clasp is broken. The brooch clasp part was silver, so it's stamped "silver" and "k18". The gold part is 18k gold. The stone is a diamond, and there's a diamond stamp of 033. It would look better if it were repaired and used. The black stone is onyx. There is also a maker's mark. It weighs 35.2g. In my case, I only used it as an obi-dome (sash clasp), so I didn't need the brooch clasp.