Rose Cut Brown Diamond Engagement Ring in 18kRose Cut Brown Diamond Engagement Ring in 18k. This amazing ring features a 1. 75 carat brown rose cut diamond and is set in 18 karat yellow gold. The warm brown diamond is very wide compared to other cuts of the same weight and it is beautifully contrasted with polished prongs of yellow gold and wreathed in a halo of white diamonds. This would make a fabulous right hand ring that you could wear every single day!