Rhodium Plated Celtic Marble Tara Brooch This beautiful rhodium plated brooch is made from Connemara marble, a unique stone featuring a range of green colour tones and known as “Ireland's gemstone”. As no pieces of marble are ever the same, each piece of our jewellery created using this stone are completely unique. The Tara brooch is named after the hill of Tara and dates back to 700AD and the era of Bronze age craftsmanship.