I picked up some very fine agate in Nova Scotia. Fine because when
cut it is perfectly clean and uniform in color.
The color is the part that is extremely difficult to describe. The
base color of the cut cabochon is a kind of gray, blue lavender,
brown. But the unusual part is that it has a clear line of
chatoyance that is a rather peach and/or orange color and then when
white light is viewed through the side of the stone, the light is
split into a red and a green line of light that plays across the
side of the stone. I have cut two stones. One has a single line of
chatoyance, the other is bigger and has three lines.
Has anyone seen anything like this? I’d love to know what to call
it.
Hi Derek, Sounds like Iris agate. The play of colors is due to
diffraction of light by very small (microcrystalline) crystals of
quartz. Will Estavillo
I’d be curious to know what particular location in Nova Scotia the
agate which you describe came from.
I’ve been collecting Nova Scotia agate for over 20 years, and
cutting it primarily into one-of-a-kind, designer stones. You can see
some of my work at Carol Bova’s site <www.bovagems.com>, click on
“showcase” and then on the “Hans Durstling Gallery”. Perhaps one of
the stones depicted there may resemble the one you describe.
One p[ossibility is that the chatoyancy of your stone may be due to
a zone of included fibrous zeolite mineral. Some of the thompsonite
from Cape d’Or for example will cut a chatoyant stone, and it is also
occasionally stained green by copper.
On the other hand you may be seeing the iris-agate effect, a silky
sort of chatoyancy which you see best when the agate is sliced very
thin and which can be accompanied by color banding. I’ve collected
some nice iris-agate from Scots Bay on the Blomidon peninsula in the
past, but this location is so accessible (you just drive right to
within 50 feel of the gravel beach), and so well known, that there’s
not a whole lot to be found there anymore.
Derek, it sounds like a piece of “Iris agate”. When cut very thin
and backlit, these pieces can show a magnificent play of color. Not
common material. Congratulations!