Lab Sapphire engagement rings? Absolutely! Diamonds may be a girl's best friend, but Lab Sapphire engagement rings are a unique, original, and a far more affordable choice. Sapphire is the birthstone of September, and one of the most popular gemstones on the jewelry scene today. The deep blue color of a sapphire ring is just right for an evening out. Once considered more valuable than diamonds, a peridot ring is a must have. This "gem of the sun" is the birthstone of August and is a beautiful match for the lush green tapestry of late summer.