Wendy's Wedding Ring

[Bob in a quantum-state-of-faith]

If you really want to know, you could test the ring's density easily enough.

It's a classic physics problem, often mentioned in intro physics: Archimedes' conundrum how to test the purity of a gold crown without melting it down.

Simple:  place the object in question into a container of liquid---typically water.  Measure the rise in liquid level, to compute the volume of said item.

Now, using it's weight, determine it's exact density.  Pure gold will have a specific value, and alloy'd gold, a different one.  I'm certain there are tables to use, to determine what level of alloy versus pure gold the ring has... it's "carat" as it were.

(yeah... I'm a science geek...)

[Swatopluk]

But consider that jewelry gold is usually slightly alloyed to improve the mechanical properties (pure gold being a bit too soft).

[Sibling Zono (anon1mat0)]

With precise enough measurements you should be able to tell if is a 10K, 12K, 14K, 18K, 20K or 24K.

[Sibling DavidH]

It's 22 carat, and this is not something I want to poke around at.  

[Bob in a quantum-state-of-faith]

That is likely an excellent plan.