Yellow Montana Sapphire Ring. This large sapphire ring has a 6mm round yellow Montana sapphire as the center piece, and simple band. Then it’s been accented with diamonds. We created this beauty in 14K white gold and you’ll find the .99ct center sapphire perfectly cut, bright and brilliant. Montana sapphires are a 9 on the Mohs hardness scale, making this lovely ring extremely durable. Wear this yellow Montana Sapphire ring for everyday or perhaps as an alternate engagement ring. Currently a size at 6 3/4 but can resize for additional charge.