I wonder if anyone has any ideas on improving the sparkle of
mounted facetted transparent stones such as citrine.
Hi Paul. better cut proportions will make all the difference you’re
I have long admired the brilliant sparkle of Swarovski
crystal. I assume the reflective backing is the reason for this,
and perhaps a major ingredient in their commercial success.
Most Swarovski crystal has no reflective backing, apart from
foilback rhinestones. Many of their pieces do have an extremely thin
coating which causes their proprietary effects, such as AB (Aurora
Borealis). Also keep in mind that Swarovski crystal is leaded glass
and not a natural crystal.
In my ignorance, (I know nothing about stone faceting), I
thought that perhaps plating a layer of silver on the back facets
(below the girdle) of a citrine would do the trick. It took me all
day to get the hang of this, and I was disappointed when I found
that the resulting stone had a distinctly dark appearance, with
significantly reduced sparkle. Is this something to do with the
angle of the facets?
No, it’s more due to the fact that you’ve changed the refractive
index of the citrine quartz. The most recognizable example is with
diamond, which tends to attract grease. When people’s diamond
jewelry becomes dull and lifeless from being constantly worn, it’s
because the dirt and grease from their fingers has changed the
refractive index of the pavilion, thereby widening the critical
angle as well. That means that light is escaping out of the bottom
instead of reflecting and refracting back up through the top, or
crown. You’ve done something similar to your citrine.
Would they need to be different if a reflective backing were
plated onto the stone, and could one expect that suitably angled
facets together with a plated reflective backing would give sparkle
to match that of Swarovski crystal?
I suppose a person could experiment with facet angles long enough to
create a pleasing effect, but remember that Swarovski uses several
different fumed coatings to get their special look. Foilbacks have
been used to make glass look better for many decades. I suggest you
look for stones with better cut proportions and facet arrangements.
For stones that tend to window, such as rectangular cut citrines,
consider taking a look at concave faceted stones.
James S. Duncan, G.G.
James in SoFl