I’m not a gemmologist; I just cut rocks. I noticed no one was
jumping right in to answer your question, so I’ll throw in my
little bit of info.
Aquamarine comes in colors ranging from sea-green (The preferred
color in the 19th century) through the green-blues and
blue-greens to icy blue and darker blue (the preferred color
today). The depth of color in a cut stone can have a lot to do
with the cut of the stone, itself. The deeper the cut, the
darker the color. Also, orientation in aqua has some effect on
depth of color. A cut with the table facet parallel to the
length of a crystal will give a darker, deeper color. Of course,
heat treating will also enhance stone color, though I’m not sure
whether that has to do with clarity or the color itself. As to
identifying your stone… 'fraid I’m not much help. I’m good at
identifying rough stone, but once they’re cut, your guess is as
good as mine! Thumbing through some of my books, it seems the
best identifier between aqua and any similar stones (apatite,
tourmaline, topaz) would be specific gravity. Aqua has a s.g. of
2.69. All others I’ve listed are over 3.00 s.g.
Hope this is of some help.
Stone Broke Custom Lapidary