3. Diffusion Star Sapphires-
Use of
chemicals/heating on the surface of the stone to change the color or add a
star to a stone that normally doesn't contain
one
4. Linde Stars(Artificial/Lab
Created Star Sapphires)-
Stone is synthetic, star and color synthetic
as
well
5. Fracture Filled-
Oil, Glass, Resin
or Epoxy fills cracks or fractures, usually unable to detect without optical
instrumentation
At Simply Sapphires, the great majority of our stones
are Natural Mined Untreated Stars, although we do carry a small few of the
others, check the individual stone listing for details.
How Can You As a consumer tell the
difference? You Can't, It really takes a well equipped
laboratory, to detect the intricate processes performed.
My experience has been jewelers and most gemologists don't have
the proper equiptment to give you anything more than an educated
guess. so if you have any question, send it to the AGTA, GIA or EGL
gem lab, or a well recognized established
lab.
Tips on What to Look For On A Star
Sapphire
1. First
thing to look at is the bottom, if there is an "L" stamped in the stone, it's
a Linde Star and synthetic... Linde stars were manufactured en masse by the
Linde division of Union Carbide since about the early 1950’s.
2. Next look for
imperfections within the stone, or an unevenness on the bottom, or stripes or
bands of color that shows through the top, most naturals have one or more of
these natural imperfections.
3. Take a good look at
the star itself, using a flashlight, most natural stars do not have a
"perfect" star, whereas the natural will likely have one or more of the six
legs uneven in length, or maybe not
perfectly straight... the star must travel around following the light source,
if the star is stationary it is definitely synthetic. The most common
synthetics jump out as way are too perfect looking and the star might only
move one direction if at all.
4. Color is extremely important, top quality
stars have top quality color, pretty simple.
5. The legs of the star should be complete and sharp, with no
missing or broken legs, and each ray should extend to the girdle of the
stone.
6. The more transparent or translucent the stone the better.
Tricky though, because sometimes with too much transparency the star is not
evident.
How rare are these gems? For every 100 faceted
corundum (ruby and sapphire) mined, approximately three stars are discovered.
One will have good color and a bad star. One will have a great star and bad
color. Only one out of a hundred will have a good star and good
color.
Fine stars are pretty rare. Until the 1960s, these
stones always sold for more than the faceted ruby. For example, in the late
19th century, three carat star rubies went for $3000 per
carat.
