Van Cleef & Arpels 18K Yellow Gold Treffle Diamond Pendant Necklace Van Cleef & Arpels Unisex Necklaces. SKU: 66373. Color: Yellow. Metal Type: Gold. Metal Stamp: 18k. Metal Weight: 4.7g. Gem stone type: Diamond. Stone weight: 0.54ct. Stone clarity: VS2. Stone color: F. Necklace style: Pendant. Chain type: Cable. Closure type: Lobster. Pre-Owned Van Cleef Arpels 18K Yellow Gold Treffle Diamond Pendant Necklace.