18kt yellow and rose gold 18kt yellow gold Solarium ring from SPINELLI KILCOLLIN featuring 18kt yellow gold, 18kt rose gold, polished finish, stackable design, chain-link detailing and Hallmarked in the United Kingdom at the London Assay Office. Conscious: We've partnered with Good On You – an ethical agency that rates how sustainably brands perform. This item comes from a brand that performs well in relation to their impact on the planet..