The name refers to the pale blue, light blue-green or even light green variety of beryl. The green of aquamarine is a watery green without any trace of yellow and is due to iron, not chromium, as can be seen from examination with a gemological spectroscope.



Appearance:
The most valuable color is a rich, sky blue; but because the stone is pleochroic, even the blue stones have a green or greenish-blue tinge in one direction. Quite large stones, ranging from several carats to more then ten or few more than ten of carats are relatively common. Many are virtually free of inclusions. (Again, where there is plenty of material available, poor quality specimens do not usually come to market.) The luster is vitreous and not exceptional. The most common cut is the emerald type, although mixed oval or pear-shaped cut are not infrequent.



Distinct features:
The color of this stone, combined with its particular type of pleochroism and vitreous luster, distinguishes it fairly easily from blue topaz and light-blue synthetic spinal, the first being a definite blue color, the second having a grey or violet tinge, much stronger luster and no pleochroism.



Occurrence:
Most aquamarines come from the pegmatites of Brazil, where crystals weighing several kilos have been found. Other deposits are in the Soviet Union (Transbaikalia, Urals, and Siberia), Madagascar, the United States, and recently, Afghanistan.



Value:
Rich blue stones several carats in weight are among the most valuable of secondary gems. They are worth a lot more, for instance, and then blue topaz of similar characteristics. Pale or green stones are much less valuable.