Caratera Fine Gold Jewellery Beautiful Womens Chakra Mala Balancing Healing Natural Sapphire 14K White Gold Necklace Matching Earrings Christmas Gift Box Set Blue sapphire belongs to the mineral species corundum. It can be a pure blue but ranges from greenish blue to violetish blue. The mineral corundum is composed only of aluminium and oxygen, and it requires a growth environment that's free of silicon. However, silicon is a very common element, making natural corundum relatively uncommon. When the trace elements are iron and titanium, the corundum is blue sapphire. Only a few hundredths of a percent of iron and titanium can cause the colour, and the more iron the corundum contains, the darker the blue. Blue sapphire come from a variety of exotic sources including Madagascar, Tanzania, Sri Lanka, Myanmar, and Australia. Sapphires are rated a 9 on the Mohs scale which is quite durable to many daily activities. FUN FACTS Ã¢ÂÂ¢ Intensely saturated and velvety, rare sapphires from Kashmir set the standard for blue. Ã¢ÂÂ¢ The world's most famous engagement ring: Kate Middleton's and Princess Diana's sapphire was 18 carats. BIRTHSTONES & ANNIVERSARIES Sapphire is the birthstone for September and the gem of the 5th and 45th anniversaries.