The Castor Boutique symbolizes the second brightest star in the Gemini Constellation, featuring our Promethean collection of styles. Castor aims to provide the vibrant color of expensive stones at attainable prices. Our Promethean styles use the most advanced lab creation techniques to emulate all of the beauty and luster of real gemstones. In addition to our Promethean styles, we have an assortment of Bianca Pearl, Black Onyx, and a variety of colored Agate jewelry. The Castor Boutique uses 925 sterling silver and 10K-18K gold for all pieces.