Salt Water Test for Amber Necklace - It Floats!

In response to a recent conversation about testing amber beads -
This is an illustration of amber floating in salt water. The amount of salt required varies somewhat in recipes found online, the most popular being one part salt dissolved in two parts water. However, it's important to remember that copal will also float in salt water, so this test is useful mainly for distinguishing natural resin from man-made plastic.

The next photo illustrates beads glowing whitish and looking opaque under UV light which many plastic and glass beads don't do.

The discussion linked below would be of interest to people who like to "dig deeper" since it goes into scientific details about the difference between copal and amber:
http://www.mindat.org/mesg-100-286019.html

The second article uses much more accessible language but presents us with pretty much the same conclusion - one can't expect to tell the difference between amber and copal without specialized equipment, since copal can get treated and as a result, respond just like amber to most testing done by an average consumer:
http://www.jtv.com/library/copal-vs-amber.html