I will try as best I can to answer that question, but as I cannot
see the stone (slab) in question this may not be precise. First,
although this part will deal with unsawed rough I think it may help.
I will add some notes at the end that may address your concerns. In
any event this (first part) is what I wrote to the IGS some years
back on how to orient the rough, to wit:
I noticed that no one wrote in about orienting Labadorite, perhaps
you can pass this along, although I feel like this is not far removed
from the adage about the blind leading the blind perhaps it will
Perhaps I should not reply as you probably have been given this
remark on the orientation of Laborite. Moreover I know very little. I
attended a rock show in Ogden and while there I bought one chunk of
this stone to play with. The guy that sold me this told me that the
most important thing with this stone when cutting it is the
To do this get your rough wet and turn it until you get a good slash
of color, mark this, it will be the "top." You will want to then saw
the rock in layers so that this color will be flat across each slab
cut. If you get more than one splash choose the strongest, I doubt
any grinding will be needed to see this color. When I bought mine I
picked out a chunk from others that were in a bucket of water and all
despite irregular shapes an area to be marked as a starting point was
Otherwise without orienting you will get a translucent gray stone
without the desired color splash.
I also noticed something else and I do not know if this is usual
with this material, or if it was just with the piece I bought. That
is, on the slab there was a stripe or zone so to speak of color flash
about 1-1/2" across while the optical properties on the other side of
this were different so I used masking tape to mark this break before
cutting it along that line. (This divide was on a healed fracture.)
When the finished cab is turned you will want the color flash across
the whole stone. So if you see this in a slab you cut to the divide
(two, instead of one big stone). This way you will be more pleased
with the results.
The fist cab I cut I did not do this above step and instead cut one
large cab. The results were a bit disappointing as often, one half
only would flash color, the other half would be a translucent gray,
and vice versa. Again I do not know if this zone is usual, at least
with that variety or not. But this zone is something to notice if
present, as I believe that usually you would want the whole cab to
flash (always). As said I know very little about this and was hoping
that someone else would write in, as I too could use some tips and
tricks on this material.
Spectrolite vs. Labadorite
Although the names Spectrolite and Labadorite are used
interchangeably this is not correct. Spectrolite is Labadorite; most
Labadorite is not Spectrolite.
Spectrolite was found in 1940 during World War II when the Finns
built a defense line on the eastern border. "Spectrolite is regarded
by gemologists as the world's most beautiful labradorite," it is
said. (This is also reflected in the price you will pay for it.) As
each country is entitled to name its own Professor Aarne
Laitakari, then Director of the Geological Survey of Finland chose
the name "Spectrolite." Spectrolite is a labradorite feldspar, a
member of the albite-anorthite series with about 55% anorthite.
If the composition is different then it is another variety (some
other names are also used, but there are different varieties with
differing properties, although I can not comment on any of those,
technically these are different. I, as said, bought it to play with
not knowing what to really expect.) The other I learned
later after seeing what this is and concluding that I want some more
From a web site we have this bit of interesting "If cut
to a normal-domed cab, the Ylaama material that we have (maybe others
as well) displays a sharp and straight cat's-eye over the
labradorescense.. I like the flat-topped cabs we produce better
though; the eye is not as evident, but the play of color is
stronger." (I can say the material I got will not cats-eye, but then
again it cost a lot less than the Ylamaa material. Although I have
one cab that is very, very nice.)
I know this is not much help. However I am very surprised that
someone with a lot more experience with this material did not reply
to your question. All I can say is that it is not hard to cut and if
oriented will produce some nice stones.
I cannot see the stone, in my hand, for that has been my greatest
teacher, i.e. some mistakes, then you know what works (or not).
(Every stone is different.) However I must assume two things, for
purpose of this instruction. First is that the slab was correctly
oriented (sawed). Second is that you want a pendant. Labradorite is
Very light directional, that is if great color is in one direction,
if turned upside down it is the opposite. Now take that slab and
turn it every way, with the light coming from above, then mark that.
This will be the top of that cab when cut, hope this helps somewhat.