With a trained eye, it is easy to identify a CZ from a diamond.
The
first tip is that CZ is always clean white and never shows visible
flaws, even under magnification. The second is that CZ is dull
and
foggy when compared to a clean white flawless diamond. But if you
are
not used to looking at diamonds, or you can't do a side by side
comparison, then you will have to take a closer look preferably with a
magnifying glass or jeweler's loupe.
First, examine the girdle (this is the widest part of the stone, where
the top and bottom angles meet). A diamond girdle is crisp and
faceted, while the girdle of a CZ is often rounded and not as clearly
defined. Most CZ's are machine cut, so all of the facet edges
throughout the stone will appear a little grainy and rounded in
comparison to a diamond.
Another easy giveaway is to look at the style of the settings.
CZ's
are usually set into plain solitaires with no accent diamonds in the
design. Most fancy ring designs with accent diamonds are set in
China
and sold in the U.S. with blank centers. When you drop a CZ into
the
center, the small diamond side stones outshine the center and the
mismatch in fire and brilliance is cause for suspicion.
The CZ water test is also fairly reliable. If you drop a diamond
into
a glass of water it will almost disappear, but a CZ will look about the
same inside of the water as it does outside.
Two other simple tests are also used, but some gemologists don't
consider them reliable. The first is a breath test. Place
the stone
close to your mouth and huff so that moisture forms on the table of the
stone. The moisture will disappear almost instantly on a diamond,
but
it will remain for 2 or 3 seconds on a CZ. The second is the
newspaper
test. Turn the stone upside down and place it directly on newsprint. If
you can read through it, it is not a diamond.
Finally, if you are at a jewelry store, most will have a thermal probe
available. This is the way most jewelers quickly test parcels of
diamonds to spot a rouge fake. You simply place the tip on the
table
of the diamond, and a meter displays if it is CZ or diamond based on
the internal density of the material.
Two final topics of warning should be noted here: first, the
thermal
probe will positively identify a CZ, but it won't confirm that the
stone is a genuine diamond. Moissanite, listed below, rates the
same
as diamond using a standard thermal probe. Second, don't try to
test a
CZ by scratching glass. Both CZ and diamonds will scratch glass
and
jewelry store owners hate this test. It is done so often that
countertops and outer windows of a jewelry store require regular
replacement. So it is really a form of vandalism.
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