Aquamarine Engagement Rings

As March is fast approaching I thought I would share some information about its birthstone aquamarine.

Aquamarine is a form of beryl along with emeralds and morganites, gaining there specific colour from the impurities within the mineral. If the stone is chromium based this classifies the stone as an emerald where as aquamarine gets it colour from the presence of iron impurities, and morganite is coloured by manganese impurities that gives the stone it’s pink, rose, peach or violet colour.

The appearance of the colour of aquamarines is watery and is found in shades of blue from sky through to dark, but it is often found naturally with a green tinge. The most desirable colour for an aquamarine is a saturated and light blue however there are also collectors who prefer the slight green tinge to be present.

Aquamarine has a hardness between 71/2 to 8 on the Mohs scale, the hardness of a morganite being the same and with emerald being slightly lower and between 7- 7½ on the Mohs scale. Even though these stones are relatively hard they are not particularly tough, and they are well known for being brittle thus easily chip or crack. Good alternative stone choices for an aquamarine is sapphire which is harder and more durable but doesn’t come with the same “watery” quality or topaz which isn’t as hard as an aquamarine but is slightly more durable and is also less precious.

Aquamarine and topaz are dichroic and pleochroic stones, aquamarine being dichroic and topaz pleochroic these terms refer to the way light reflects with-in the stone and then what the eye perceives. This is quite a difficult and scientific fact to explain but I think the best and easiest explanation of this is that I have found is from www.allaboutgems.com.

Pleochroism

‘As light emerges from a doubly refracting transparent stone, the beam is split into two polarised light rays, each vibrating in planes at right angles to each other. If the light beam emerges from a colored stone, each new refractive indices may undergo a different degree of color absorption. Minerals in the isometric crystal system cannot exhibit any type of pleochroism.’

Dichroism

‘Unlike pleochroism which is not dependent on the viewing angle, ‘dichroism’ (from the Greek word dikhroos, meaning ‘two-colored’) is when two colors are perceived when observing the stone from two different directions (unlike dispersion). Minerals in the hexagonal, tetragonal, and trigonal crystal system are dichroic, and can only show two colors. In the field of optics, dichroism is sometimes used to denote pleochroism as described above.’

The popularity of the aquamarine increased in around the 1920’s when the development of heat treating the stone resulted in deeper shades in very pale stones; heat treating the stone can also remove the green tinge that is often present. The stone was also traditionally known as a sailor’s talisman and it is often associated with the qualities of happiness and understanding – so a good choice for an engagement ring!