It is marked 14k on the top of the pin stalk which is yellow gold. I took it to a jeweler who told me the top is platinum and the oval green stone is a smooth top Green Tourmaline, and it is faceted on the backside. It has a tiny seed pearl accent and it has a silver colored clutch which is probably plated metal. It is 2.75" long; the top section is a little over 1/2" wide by about 1/2 tall. In really nice shape with hardly any wear, I've not cleaned it and have left it as found, the green tourmaline faces up medium to darker green.Without the clutch it weighs 1.6 pennyweights or about 2.48 grams. Ask questions and look at my pictures. The item "Art Nouveau 14k Platinum Pearl & Green Tourmaline Cabochon Stickpin" is in sale since Sunday, January 31, 2021. This item is in the category "Jewelry & Watches\Vintage & Antique Jewelry\Fine\Art Nouveau/Art Deco 1895-1935\Pins, Brooches". The seller is "mishdish59" and is located in Groton, Connecticut. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Viet nam, Uruguay, Russian federation.