Rhodochrosite, opal, pearl, quartz and silver necklace. Rhodochrosite is a manganese mineral and the state gemstone for Colorado. Opal is an opague mineral formed from silica and water. Pearls are created in the living mollusk. Quartz is a rock crystal found in the earth's crust. Great for casual, business and dressy styles! It is 20.5 inches and weighs 4.0 ounces. Gorgeous clip on earrings that compliment this necklace is pictured below.