7x5mm Octagon Emerald Cut Gem Quality Chatham Lab-Grown Blue Sapphire Weighs 1.05-1.28 Ct, Medium Tone. Octagon Emerald Cut Gem Quality Blue Sapphire Weighs 1.05-1.28 Ct. Chatham Created Blue Sapphire Limited Lifetime Warranty Certificate of Authenticity Premium Quality Flux Grown