19 karat green gold is Jill Platner’s unique alloy, created in house, using her special blend of high-karat gold with sterling silver and trace amounts of copper, resulting in a sumptuous, bold hue. These simple hammered 19k gold studs are perfect for everyday wear. -0.25" wide. -0.375" post. Inspired by both organic and urban forms, Jill Platner uses her background as a sculptor to create jewelry that is known for its fluid sense of movement and tactile quality. Made by hand in her studio in New York City, her jewelry designs are conceived with an innate sense of how they will look and feel on the body and all share a timeless wearability.