I have always found stones with self describing names intriguing;
sometimes the name is indirectly describing the stone. One example of this is
“bloodstone”, today this refers to a form of quartz that is primarily dark green
but has blotches of red. This mineral is sometimes called heliotrope but more commonly called bloodstone
today. Historically hematite, which was derived from the Greek word for blood,
was called “bloodstone” or “blood ore”. Hematite in its powdered form can be
red (rouge). Hematite is also a high grade iron ore and the coolant water could
also turn red from the oxidized iron (rust).
Recently I’ve been studying
sunstone and found that a number of minerals have been called “sunstone”, in fact
many people use the term “Aventurine Feldspar” to differentiate it from its
quartz counterpart. The quartz counterpart is a relatively rare “orange”
variety of Aventurine. The “orange Aventurine has the quality of
Aventurescence
and looks similar to the Aventurine Feldspar or Sunstone.
Aventurine Feldspar is usually found in
a “massive” form and is commonly called Sunstone; below we will see it called
Oligoclase. When Aventurine Feldspar is in a crystalline form it’s usually
referred to as Heliolite it can be a number of colors but is usually golden
yellow and has a clear to cloudy appearance. Occasionally Aventurine Feldspar is
truly stunning and is very clear with bright colored inclusions and is called
Oregon Sunstone.
Recently a fellow named Fossheim
Steinsenter identified three minerals that he thought might be the Norse
sunstone and that were available in the Norse world. He published a video that
shows an example of each mineral and also has a website at www.fossheimsteinsenter.no.
Unfortunately I have not been able to connect with it but I did watch the video
on U-Tube. The three minerals that Fossheim identified are Oligoclase Feldspar,
Cordierite, and Icelandic Feldspar. Oligoclase Feldspar is usually found in
more complex minerals such as granite but is closely associated with
Aventurine
Feldspar or modern day Sunstone. We discussed this mineral earlier so I will
move on to Cordierite.
Cordierite is usually found in massive forms or within more complex
minerals and can be a number of colors. However when thinly sliced it is
bluish. The gem form of Cordierite is Iolite and this was the most interesting
mineral yet. The name "iolite" comes from the Greek word for violet.
Iolite was also called dichroite,
a Greek word meaning "two-colored rock", a reference to cordierite's
strong pleochroism.
When Iolite is turned it changes color on a clear plane usually blue/violet to
translucent white. I thought that this was interesting and spent a great deal
of time trying to apply this characteristic to finding the sun. Incidentally it
has also been called "water-sapphire" and "Vikings'
Compass" because it was long believed to be the “sunstone” used by the
Norsemen. However I could not find a way to apply the pleochroism to “finding”
the sun. So I move on to Icelandic Feldspar.
Iolite was very interesting and
fun to play with but Icelandic Feldspar proved to be very exciting. The history
of this next mineral is more speculative but, in my opinion, accurate. We call
the mineral Iceland spar but I believe that the Norsemen referred to it as “sunstone”.
The Norse folks are known for being daring seamen well ahead of their time and
are probably the first to fish cod off of North America.
The Viking heyday was around 800 AD to 1250 AD, depending on whom you ask, but
their advanced knowledge continued well into the 16th century.
During that time rumors contained
references to “sunstone” a magical stone that could “find the sun”. These
rumors turned into vague references to such a stone in later saga and poems.
Then quite recently divers found the “Alderney Crystal” on the canon of a 16th
century wreck. The crystal showed appropriate signs of exposure to the ocean
and was resting next to a pair of navigation dividers also showing appropriate
signs of exposure to the ocean.
Many scientists of today stop
short of connecting Iceland spar to the Norse sunstone because there is not a
clear written record of such a stone and certainly not a clear description of
how it might have been used. But, from my reading, I am convinced that they are
one in the same. Frankly I did have some issue with some of the reports about
the circumstance of its use. However nothing as bad as the questions I have
about the “eye witness” narratives from other times in history. The main issue
is the weather descriptions given when the sunstone was used, remembering that
these are, at least, second hand descriptions. The description indicates fully
clouded skies but in my understanding, the Iceland spar does not work under
these conditions. I stopped to reassure myself and remembered that “stories” do
change with the telling and the sky can become more and more clouded with each
rendition of the drama.
Another point must be remembered,
the world of the Norsemen was different than it is today, the North
Atlantic was experiencing the Medieval Warm Period (MWP) so the
climate was much warmer. Under these conditions the major daily problems for
the Norsemen were dense fog on the horizon and a sun that did not rise very far
above the horizon for long periods of time. I’m not implying that there were
not intermittent storms, that certainly happened also. This combined with the
lack of a compass, which even if a crude compass did exist, its accuracy would
not have been up to use so close and often within the Artic Circle.
So back to the Iceland spar, the “sunstone”
was easily available in the Scandinavian world of this period. Scandinavians
are smart and inquisitive; someone would have noticed the quality of birefringence
or double refraction. This quality causes objects viewed through the Iceland spare
to appear doubled. This quality was quantified by Danish scientist in 1669,
probably much to the amusement of those whose ancestors had been using it for
centuries. Today folks refer to this quality as “linearly polarizing”. However
the term “depolarizing” seem more appropriate to me. When held up to the sky
there is an angle of rotation where the Iceland spar eliminates all
polarization of the light. This is called the isotropy point. The problem is
that a patch of blue sky is needed, the heavier the overcast the less effective
the depolarizing affect.
The use of the Iceland spar needs
some practice and a mark or an indicator attached to the Iceland spar must be
used to “point” to the sun when the isotropy point is found.
Presently I am at the point of
devising an “instrument” for holding the Iceland spar and indicating the
direction of the sun. Although even the accepted references to the use of the
sunstone indicate that the stone was used “in hand” and not housed in a nice
little box.
There is the one example shown
but time will tell what mine will look like.
WORDS TO REMEMBER;
Clarke's Three Laws are
three "laws"
of prediction formulated by the British writer Arthur C.
Clarke. They are:
When a
distinguished but elderly scientist states that something is possible, he is
almost certainly right. When he states that something is impossible, he is very
probably wrong.
The only way of
discovering the limits of the possible is to venture a little way past them
into the impossible.
Any sufficiently
advanced technology is indistinguishable from magic.
Have a great day!
