Oval Sillimanite/Fibrolite Cats Eye Ring / Cats Eye Jewelry Beautiful AAA quality and rare black Sillimanite Cats Eye (aka Fibrolite) is encased in copper with your choice of Bright or Antique Copper finish. Each perfect little oval stone measures 5 x 7mm. Among the gemstones that display special optical phenomena, cat's eye gems are particularly interesting, in part because the effect is found in so many different gem varieties. The technical term for the cat's eye effect is chatoyancy, derived from the French for eye of the cat ("oeil de chat"). Bright Copper or Antique Copper finish. Organic, natural style handmade ring. Made to order - Ready to ship in one week. Due to the nature of raw stone rings and individual pieces are made by hand, each piece will be slightly different and therefore unique. Custom sizes available - from US size 1 through 16 including 1/4 and 3/4 sizes. Choose Custom and include size in Note from Buyer box at checkout. Rings are made via electroforming, resulting in a pure copper ring. Copper is hypoallergenic. Blackbird & Sage creates handcrafted crystal and gemstone copper jewelery for the modern bohemian. Gemstones are always hand selected and our designs include raw gemstones, raw crystals and classic cut high quality cabochon stones. We believe in simple, local and purposeful craftsmanship, which we hope is reflected in our pieces. At Blackbird & Sage, we want to give you the ability to wear something that has a personal story, built from love and has a unique and special meaning to you. As we work with raw and rough stones please expect that your piece will vary slightly in shape and color from those shown in the photograph. Your stone will not vary in quality from that shown, so rest assured your piece will be truly unique and beautiful. All our copper rings are left without treatment, so you can benefit from it's healing properties. - Bright copper has a lustrous shine and will darken over time. Copper can easily be cleaned back to a bright shine. Just wipe with a jewelry cloth to brighten it up again. - Aged copper gives the ring an antique look which will brighten as you wear it, leaving you with a beautiful natural and shiny aged ring.