Optical Calcite
(aka)    "Iceland Spar"
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Museum Specimens

This variety of Calcite is called "Iceland Spar", which is basically clear cleaved fragments of completely colorless (ice-like)
calcite. Originally discovered in and named after Eskifjord, Iceland. The Iceland spar displays the classic cleavage form of
calcite, the rhombohedron. Iceland Spar is used for optical equipment and during World War II it was an extremely important
mineral that was used in the sighting equipment of bombardiers and gunners. Our specimens come from the locations
currently producing the most interesting specimens for collectors. We are always looking for more locales.

“A secret mine in the mountains west of the Salton Sea contained the only available source of a particular calcite crystal
needed to make the famous “Norden Bombsight”.  This transparent crystal formation is also known as Iceland Spar because
it is found in cavities in the solidified lava of which Iceland is made.  The war in Europe had made shipping in the North
Atlantic very precarious and the United States needed another source of this precious commodity.  The Norden bombsight
was one of the most important military secrets of World War II; it made possible the very accurate European bombing raids
which helped bring the war to a close.  It was so advanced that bombardiers had to take an oath to protect its secrecy with
their lives.  Arthur LaLonde remembers that one of his first assignments in the military was to search, with four other men, the
snowy summit of Mt. San Jacinto for the Norden bombsight carried on a plane that had crashed there.  Locals who worked
the mine remember that it was guarded by Marines and worked around the clock.  The mine is now within the boundaries of
Anza-Borrego State Park, north of the Salton City Borrego Springs highway.”
Source:  The Periscope 2001 - Publication of the Coachella Valley Historical Society

Iceland spar demonstrates the unique property of calcite called birefringence (double refraction). Double refraction occurs
when a ray of light enters the crystal and due to calcite's unique optical properties, the ray is split into fast and slow beams.
As these two beams exit the crystal they are bent into two different angles (known as angles of refraction) because the angle
is affected by the speed of the beams. A person viewing into the crystal will see two images ... of everything. The best way to
view the double refraction is by placing the crystal on a straight line or printed word. The result will be two lines or two words
visible through the calcite. The thickness and the angle of the Calcite determines the distance between lines or text as can
be seen in the photos in our listings. Turning or rotating the calcite increases or decreases the space between the two lines
or words (double refraction) that this mineral is famous for. Different sides of the rhomb give different separation  distances
for the double refraction as well. These are very educational and interesting pieces!
Item # 25LOCM03175994
Very Rare 328g Lavender
Optical Calcite from Madagascar
Very Rare AAA Grade 328g Lavender Tint Clear Optical Calcite from Madagascar
This specimen measures 3.6 x 2.9 x 1.4 inches (9.1 x 7.4 x 3.6cm) and weighs 11.5oz  or 0.72 lb (328g)

We were happily surprised in our never ending search for quality Optical Calcites when we found these Optical Calcite
Crystals from the Mahajanga Province of Madagascar.  We have sold many Optical Calcite Crystals over the past few
years from Mexico, China and Brazil. The most popular so far have been the Brazilian crystals that are polished with
beveled edges.  The Optical Calcite crystals from Madagascar are a new find and are not known to most collectors... yet
that is... we are sure they will become highly sought after very quickly. Madagascar Optical Calcite crystals are the
clearest of them all and some have very bright rainbow reflections.  Quite a few have a stunning subdued Lavender tint.  
Of all locales, these are hands down the rarest. Excellent Birefringence.
Item # 51CPB04165953
222g Polished Optical Calcite from Brazil
AAA Grade 222g Polished Clear Optical Calcite from Brazil
This specimen measures 2.18 x 1.5 x 1.42 inches (55.5 x 38.2 x 36.1mm) across the flats, or it
measures 2.98 x 2.41 inches (75.7 x 61.3mm) across the diagonals.
This piece weighs 7.8oz or 0.49 lb (222g)

We were lucky in our search for quality Optical Calcite from Brazil when we found these nicely
polished rhombs with lightly rounded chamfered edges that were finished in Brazil. We selected a
few of the nicest pieces and hope to be able to procure more of these excellent specimens in the
future. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction shows! This
piece is crystal clear and has interesting natural internal fractures and rainbows . The piece is
polished on all sides. It has a few corner dings as shown in the photos, still an amazing
specimen! A quality work of art from Brazil with a great price for a quality specimen!
Item # 52CPB04165953
204g Polished Optical Calcite from Brazil
AAA Grade 204g Polished Clear Optical Calcite from Brazil
This specimen measures 1.82 x 1.59 x 1.53 inches (46.4 x 40.5 x 39mm) across the flats, or it
measures 2.69 x 2.11 inches (68.3 x 53.7mm) across the diagonals.
This piece weighs 7.2oz or 0.45 lb (204g)

We were lucky in our search for quality Optical Calcite from Brazil when we found these nicely
polished rhombs with lightly rounded chamfered edges that were finished in Brazil. We selected a
few of the nicest pieces and hope to be able to procure more of these excellent specimens in the
future. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction shows! This
piece is crystal clear and has interesting natural internal fractures and rainbows . The piece is
polished on all sides. It has a few corner dings as shown in the photos, still an amazing
specimen! A quality work of art from Brazil with a great price for a quality specimen!
Item # 26LOCM03175992
Very Rare 171g Lavender
Optical Calcite from Madagascar
Very Rare AAA Grade 171g Lavender Tint Clear Optical Calcite from Madagascar
This specimen measures 2.8 x 2.3 x 1.1 inches (7.2 x 5.8 x 3cm) and weighs 6oz  or 0.37 lb (171g)

We were happily surprised in our never ending search for quality Optical Calcites when we found these Optical Calcite
Crystals from the Mahajanga Province of Madagascar.  We have sold many Optical Calcite Crystals over the past few
years from Mexico, China and Brazil. The most popular so far have been the Brazilian crystals that are polished with
beveled edges.  The Optical Calcite crystals from Madagascar are a new find and are not known to most collectors... yet
that is... we are sure they will become highly sought after very quickly. Madagascar Optical Calcite crystals are the
clearest of them all and some have very bright rainbow reflections.  Quite a few have a stunning subdued Lavender tint.  
Of all locales, these are hands down the rarest. Excellent Birefringence
Item # 27LOCM03175913
Very Rare 163g Lavender
Optical Calcite from Madagascar
Very Rare AAA Grade 163g Lavender Tint Clear Optical Calcite from Madagascar
This specimen measures 2.8 x 2.3 x 1.1 inches (7.1 x 6 x 3cm) and weighs 5.7oz  or 0.36 lb (163g)

We were happily surprised in our never ending search for quality Optical Calcites when we found these Optical Calcite
Crystals from the Mahajanga Province of Madagascar.  We have sold many Optical Calcite Crystals over the past few
years from Mexico, China and Brazil. The most popular so far have been the Brazilian crystals that are polished with
beveled edges.  The Optical Calcite crystals from Madagascar are a new find and are not known to most collectors... yet
that is... we are sure they will become highly sought after very quickly. Madagascar Optical Calcite crystals are the
clearest of them all and some have very bright rainbow reflections.  Quite a few have a stunning subdued Lavender tint.  
Of all locales, these are hands down the rarest. Excellent Birefringence  
Displays rainbow colors!
Item # 28LOCM03175912
Very Rare 29g Lavender Optical
Calcite from Madagascar
Very Rare AAA Grade 29g Lavender Tint Clear Optical Calcite from Madagascar
This specimen measures 1.5 x 1.2 x 0.75 inches (3.8 x 3.2 x 1.9cm) and weighs 1oz (29g)

We were happily surprised in our never ending search for quality Optical Calcites when we found these Optical Calcite
Crystals from the Mahajanga Province of Madagascar.  We have sold many Optical Calcite Crystals over the past few
years from Mexico, China and Brazil. The most popular so far have been the Brazilian crystals that are polished with
beveled edges.  The Optical Calcite crystals from Madagascar are a new find and are not known to most collectors... yet
that is... we are sure they will become highly sought after very quickly. Madagascar Optical Calcite crystals are the
clearest of them all and some have very bright rainbow reflections.  Quite a few have a stunning subdued Lavender tint.  
Of all locales, these are hands down the rarest. Excellent Birefringence  
Item # A-GBOPTCAL11179975
285g A Grade Optical Calcite
from Brazil Polished in
Idar-Oberstein

$116.00
A Grade 285g Clear Optical Calcite from Brazil, Polished in Idar-Oberstein
This specimen measures 3.7 x 2.9 x 1.21 inches (94.7 x 75.9 x 30.9mm) and weighs 10oz  or 0.629 lb (285g)

We were able to procure a few special specimens in our never ending search for quality Optical Calcites when we found
this Optical Calcite Crystals from Mato Grosso do Sol, Brazil that was ground and polished in Idar-Oberstein, Germany
(Deutchland).  We have sold many Optical Calcite Crystals over the years from Mexico, China, Madagascar and Brazil.
The most popular so far have been the Brazilian crystals that are polished with beveled edges.  The best of these
Brazilian Calcites are the ones ground and polished by the artisans in Idar-Oberstein. Of all Optical Calcites we have
ever come across, these Idar-Oberstein calcites are hands down the highest quality clarity with excellent Birefringence.
Item # B-GBOPTCAL11173396
201g AAA Grade Optical Calcite
from Brazil Polished in
Idar-Oberstein

$168.00
AAA Grade 201g Clear Optical Calcite from Brazil, Polished in Idar-Oberstein
This specimen measures 3 x 2.44 x 1.15 inches (78.1 x 62.2 x 29.3mm) and weighs 7.08oz  or 0.44 lb (201g)

We were able to procure a few special specimens in our never ending search for quality Optical Calcites when we found
this Optical Calcite Crystals from Mato Grosso do Sol, Brazil that was ground and polished in Idar-Oberstein, Germany
(Deutchland).  We have sold many Optical Calcite Crystals over the years from Mexico, China, Madagascar and Brazil.
The most popular so far have been the Brazilian crystals that are polished with beveled edges.  The best of these
Brazilian Calcites are the ones ground and polished by the artisans in Idar-Oberstein. Of all Optical Calcites we have
ever come across, these Idar-Oberstein calcites are hands down the highest quality clarity with excellent Birefringence.
Item # C-GBOPTCAL11172666
147g AAA Grade Optical Calcite
from Brazil Polished in
Idar-Oberstein

$164.00
AAA Grade 147g Clear Optical Calcite from Brazil, Polished in Idar-Oberstein
This specimen measures 2.57 x 2 x 1.25 inches (65.3 x 51 x 31.7mm) and weighs 5.1oz  or 0.32 lb (147g)

We were able to procure a few special specimens in our never ending search for quality Optical Calcites when we found
this Optical Calcite Crystals from Mato Grosso do Sol, Brazil that was ground and polished in Idar-Oberstein, Germany
(Deutchland).  We have sold many Optical Calcite Crystals over the years from Mexico, China, Madagascar and Brazil.
The most popular so far have been the Brazilian crystals that are polished with beveled edges.  The best of these
Brazilian Calcites are the ones ground and polished by the artisans in Idar-Oberstein. Of all Optical Calcites we have
ever come across, these Idar-Oberstein calcites are hands down the highest quality clarity with excellent Birefringence.