Optical Calcite
(aka)    "Iceland Spar"
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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 came from Santa Eulalia
District, Mexico

“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
Item # ISCOC05130150
14g Iceland Spar Light Yellow Optical
Calcite From Mexico
$9.00
14g Iceland Spar Light Yellow Optical Calcite from Mexico
This specimen measures 1.23 x 0.87 x 0.26 inches (31 x 22 x 6.7mm) and weighs 0.48oz (14g)
Item # ISCOC12135934
207g Cleaved Optical Calcite
from Brazil
$96.00
207g Cleaved Clear Optical Calcite from Brazil
This specimen measures 1.7 x 1.6 x 1.6 inches (43 x 41 x 41mm)
and weighs 7.3oz or 0.458 lb (207g)

This is a nice piece of Optical Calcite from Brazil. This specimen has  been
cleaved in rhombohedral shape. Minor chips are visible on edges.  
Specimens from Brazil are in demand more than any other locale due to the
definitive visual separation of double images seen through the calcite. Look
how well the bi-refraction shows! (the brown coloring is a reflection, this piece
is crystal clear!) There are small natural fractures, with many rainbows visible.
The piece is nicely cleaved on all sides and displays beautifully!
Item # ISCOC05138756
Very Rare 112g Polished
Optical Calcite from Brazil
$139.00
Very Rare 112g Polished Clear Optical Calcite from Brazil
This specimen measures 2.5 x 1.5 x 0.63 inches (63 x 38 x 16mm) and weighs 3.94oz (112g)

We were happily surprised in our search for quality Optical Calcite from Brazil when we found a
supplier from the famous German Lapidary Town of Idar-Oberstein. We selected a few of their nicest
pieces and hope to be able to procure a couple of these excellent specimens each year from our
new found source. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction
shows! (the brown coloring is a reflection, this piece is crystal clear!) There is a small inclusion and
natural fracture on one of the edges. The piece  is polished on all sides and has polished chamfered
edges. A true work of art from Idar-Oberstein!
Item # ISCOC07136186
Very Rare 170g Polished
Optical Calcite from Brazil
$195.00
Very Rare 170g Polished Clear Optical Calcite from Brazil
This specimen measures 3.39 x 1.42 x 0.75 inches (86 x 36 x 19mm) and weighs 5.98oz (170g)

We were happily surprised in our search for quality Optical Calcite from Brazil when we found a
supplier in the famous German Lapidary Town of Idar-Oberstein. We selected a few of their nicest
pieces and hope to be able to procure a couple of these excellent specimens each year from our
new found source. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction
shows! (the brown coloring is a reflection, this piece is crystal clear!) The piece is polished on all
sides and has polished chamfered edges. A true work of art from Idar-Oberstein!
Item # ISCOC12139264
Very Rare 111g Polished
Optical Calcite from Brazil
$130.00
Very Rare 111g Polished Clear Optical Calcite from Brazil
This specimen measures 1.9 x 1.7 x 0.7 inches (49 x 43 x 18mm) and weighs 3.9oz (111g)

We were happily surprised in our search for quality Optical Calcite from Brazil when we found a
supplier in the famous German Lapidary Town of Idar-Oberstein. We selected a few of their nicest
pieces and hope to be able to procure a couple of these excellent specimens each year from our
new found source. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction
shows! This piece shows rainbows and is crystal clear and has natural internal fractures. The
piece is polished on all sides and has polished chamfered edges.
A true work of art from Idar-Oberstein!
Item # ISCOC09130550
Rare 55g Clear Optical Calcite
from Brazil
$26.00
Rare 55g Clear Optical Calcite from Brazil
This specimen measures 1.4 x 1.2 x 0.7 inches (36 x 31 x 18mm) and weighs 1.9oz (55g)
We were happily surprised in our search for Optical Calcite from Brazil when we found this clear
cleaved piece of Brazilian Optical Calcite. There are internal natural fractures that produce amazing
rainbows. Excellent bi-refraction as shown in the photo.
Item # ISCOC07137889
Rare XL 553g Optical Calcite
from Mina Prieta Linda, Mexico
$189.00
Rare XL 553g Optical Calcite from Chihuahua, Mexico
This specimen measures 3.78 x 3.48 x 0.93 inches (9.6 x 8.8 x 2.3cm) and weighs 19.5oz (1.22 lb)

Almost 1 and 1/4 pounds of exceptional Iceland Spar (Optical Calcite) from Mina Prieta
Linda, Naica, Chihuahua, Mexico. This piece is a terrific extra-large specimen of
near-optical quality Iceland Spar (Calcite). The specimen is very sharply cleaved in
rhombohedral form. The piece comes from the Mina Prieta Linda, Naica, Chihuahua,
Mexico. Aside from its striking beauty and optical clarity, the most interesting thing about
the specimen is that it has the property of double refraction - that is, when looking through
the crystal, objects appear double! Also, as an added feature, this piece is prismatic,
creating multiple rainbows when viewed from the correct angles. This is another treasure
from our personal collection that came from the 2008 Tucson Show.
Polished in Idar-Oberstein, Germany
Polished in Idar-Oberstein, Germany
Polished in Idar-Oberstein, Germany
Item # ISCOC12134995
Very Rare 161g Polished
Optical Calcite from Brazil
$154.00
Very Rare 161g Polished Clear Optical Calcite from Brazil
This specimen measures 2.5 x 1.1 x 1.1 inches (64 x 30 x 29mm) and weighs 5.6oz (161g)

We were happily surprised in our search for quality Optical Calcite from Brazil when we found a
supplier in the famous German Lapidary Town of Idar-Oberstein. We selected a few of their nicest
pieces and hope to be able to procure a couple of these excellent specimens each year from our
new found source. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction
shows! This piece shows lots of rainbows and is crystal clear and has natural internal fractures.
The piece is polished on all sides and has polished chamfered edges.
A true work of art from Idar-Oberstein!
Item # ISCOC12136995
Very Rare 167g Polished
Optical Calcite from Brazil
$159.00
Very Rare 167g Polished Clear Optical Calcite from Brazil
This specimen measures 1.7 x 1.6 x 1.2 inches (44 x 41 x 32mm) and weighs 5.8oz (167g)

We were happily surprised in our search for quality Optical Calcite from Brazil when we found a
supplier in the famous German Lapidary Town of Idar-Oberstein. We selected a few of their nicest
pieces and hope to be able to procure a couple of these excellent specimens each year from our
new found source. Polished Optical Calcite is a Real Treasure! Look how well the bi-refraction
shows! This piece is crystal clear except one corner has interesting milky inclusions. As do all
optical calcites, it has natural internal fractures. The piece is polished on all sides and has
polished chamfered edges. A true work of art from Idar-Oberstein!
Polished in Idar-Oberstein, Germany
Polished in Idar-Oberstein, Germany