can you tell me if this piece of equippment is worth
purchasing, its called a darkfeild Diamond viewer its helps you see
flaws and fracture filled diamonds?
Hi Lawrence. The answer to your question is yes, it is worth
purchasing if you know how to use it. The darkfield viewer you
mention is basically a loupe that is mounted in such a way as to
provide "darkfield illumination" when used with a flashlight (or
hand torch, as our UK friends often name it), which is also usually
supplied with the loupe. Darkfield illumination is basically a way
to view any stone, not just diamonds, with lighting from all sides
with a black background that provides much more relief, or contrast,
than you can get from light that is transmitted directly through the
stone (brightfield illumination). More relief means that it is much
easier to see inclusions and fracture filling, as well. The down
side is that simply having darkfield illumination does not mean that
you will automatically be able to see filled fractures in diamonds.
You will certainly be able to see any poorly filled fractures due to
the high relief of gas bubbles, but a well-filled stone may have
none. To see a well done fill, you'll have to view it from the side,
while rocking the diamond back and forth, as you look for something
called "the flash effect". It can certainly be confused with the
rainbow colors you see in a regular, unfilled fracture, except that
the flash effect is pinkish-purple in color. Also, some fracture
fills may require overhead lighting instead of darkfield to reflect
off of the glass filler in the fracture so that it may be detected.
To sum up; yes, a darkfield loupe, or "viewer" is a worthwhile
investment if you need darkfield illumination out in the field or at
a trade show, etc. But there is definitely no substitute for a
darkfield/brightfield/overhead lit gemological microscope for
detecting fracture filled stones and their various inclusions.