Aquamarine, named for the Latin phrase “water of the sea”, is the blue to blue-green variety Beryl. Beryl also contains other gem varieties, including Emerald, and some lesser known varieties such as Morganite and Heliodor. Aquamarine ranges in colour from a faint light blue to blue and bluish-green, with lighter coloured stones being the more common type. Light green Beryl can be transformed into Aquamarine if heated to 750º F (400º C). The green hues in most Aquamarine can also be removed through heat treatment.
Sapphire is the most precious and popular blue gemstone. It is a very desirable gemstone due to its excellent colour, hardness, and durability. Sapphire without any colour prefix refers to the blue variety of the mineral Corundum. However, the term Sapphire encompasses all other gem varieties and colours of Corundum as well, excluding Ruby, the red variety of Corundum, which has its own name since antiquity.
Blue sapphires are found in a number of locations around the world including Kashmir, Myanmar, Sri Lanka, Madagascar, Thailand, Australia, Tanzania, and the state of Montana in the United States.
Emerald, the green variety of Beryl, is the most famous and valuable green gemstone. Its beautiful green colour, combined with durability and rarity, make it one of the most expensive gemstones. Deep green is the most desired colour in Emeralds. In general the paler the colour of an Emerald, the lesser its value. Very pale coloured stones are not called Emeralds but rather “Green Beryl”. They are sometimes heat treated, which causes their colour to turn blue and transform into Aquamarine.
Moissanite is a high quality synthetic gemstone which imitates the appearance of diamonds and is made in a lab. It is created with silicon and carbon, through a combination of pressure and heat. Moissanite is a name given to silicon carbide (chemical formula SiC) for use in the gem business.
Morganite’s subtle colour is caused by traces of manganese. Because morganite has distinct pleochroism pale pink and a deeper bluish pink (salmon colour) it’s necessary to orient the rough carefully for fashioning. Strong colour in morganite is rare, and gems usually have to be large to achieve the finest colour. Morganite crystals can be large, originating from Brazil.
Pink sapphires come in very pale pastel pinks to vibrant and intense hot pinks. Pink sapphires are coloured by traces of chromium. Lower concentrations of chromium create pink sapphires while very high chromium concentrations will create a ruby. If the trace element titanium is included in the crystal structure, the sapphire will have a more purplish pink hue. Pink sapphires belong to the corundum family of minerals. They contain traces of iron, titanium, magnesium, copper and chromium that help determine its colour. The higher the chromium content, the deeper the pink hue. The leading producer of pink sapphire originates in Madagascar.
A Ruby is a pink to blood-red coloured gemstone. In its purest form, the mineral corundum is colourless. Trace elements that become part of the mineral’s crystal structure cause variations in its colour. Chromium is the trace element that causes ruby’s red, which ranges from an orangey red to a purplish red. The strength of ruby’s red depends on how much chromium is present. The more chromium, the stronger the red colour. Chromium can also cause fluorescence, which adds to the intensity of the red colour. The word ruby comes from ruber, Latin for red.
Yellow sapphires are the most sought after colour in today’s jewelry industry after blue sapphires. Many yellow sapphires are thought to closely resemble yellow diamonds. They can range in colour from bright canary yellow to greenish yellow, to everything in between. While customers tend to prefer a yellow sapphire colour that is a medium, vibrant canary yellow, a deep, orangish yellow (whisky colour), is highly valued in some Asian markets.