18KTGP Pump Brooch with a Black Onyx Finish and Braided GP Accents. The colour gold is associated with wealth, excess, and extravagance. It has also been linked to love, illumination, compassion and wisdom. Black Onyx is the anniversary gemstone for the 10th year of marriage. Onyx is a variety of the microcrystalline quartz, called chalcedony. Genuine Natural High Quality Brooch With Semi-Precious Stones. The Brooch Has Hand Settings & Were Classis Vintage & Crafted Finishes Nickel Allergy Free, Base Metal- Brass, 18KTGP Yellow Gold Electroplate Finish. View Photos for Further Details.