grandidierite

Name: Grandidierite

Origin: Andrahomana, Madagascar

Size: 3x2cm

very rare

ORIGINS OF GRANDIDIERITE

GRANDIDIERITE IS A RELATIVELY LITTLE KNOWN AND EXTREMELY RARE STONE. IT WAS DISCOVERED IN THE CLIFFS OF ANDRAHOMA, ON THE SOUTH COAST OF MADAGASCAR. IT IS ALSO FOUND IN ALGERIA, ANTARCTICA, CANADA, CZECH REPUBLIC, INDIA, ITALY, MALAWI, NEW ZEALAND, NORWAY, SRI LANKA AND THE UNITED STATES. HOWEVER, FACETTABLE GRANDIDIERITES LARGER THAN ONE MILLIMETERE HAVE ONLY BEEN DISCOVERED IN MADAGASCAR AND SRI LANKA.

COMPOSITION OF GRANDIDIERITE

GRANDIDIERITE IS A BOROSILICATE OF MAGNESIUM, IRON AND ALUMINUM. THE MORE THE BLUE COLOR DOMINATES, THE MORE THE STONE CONTAINS IRON. THIS NATURAL AND UNTREATED STONE IS CHARACTERIZED BY ITS INCLUSIONS, ALTHOUGH THERE ARE ALSO SMALL FACETED EXAMPLES. THESE INCLUSIONS, LITTLE PIN-SHAPED “CHANNELS”, AND THE FACT THAT THESE EXTEND THROUGHOUT THE GEMSTONE REPRESENT THE BIGGEST CHALLENGE WHEN CUTTING.

HISTORY OF GRANDIDIERITE

GRANDIDIERITE, A DEEP OCEAN OR LAGOON BLUE GEMSTONE, WAS DISCOVERED IN MADAGASCAR IN 1902. IT WAS NAMED IN HONOR OF FRENCH EXPLORER AND NATURALIST ALFRED GRANDIDIER (1836-1921) WHO STUDIED NATURAL HISTORY FROM THE ISLAND.

THE COLORS OF GRANDIDIERITE

THIS TRANSPARENT TO TRANSLUCENT STONE FEATURES GORGEOUS TONES OF GREENISH BLUES AND BLUISH GREENS. SPECIMENS WERE ALSO FOUND WITH TRICHOITIC PLEOCHROISM (SEE PAGE 36), THAT IS TO SAY THAT THE STONE HAS THREE COLORS DEPENDING ON THE ANGLE OF OBSERVATION: DARK BLUE-GREEN, COLORLESS (EVEN VERY LIGHT YELLOW) AND DARK GREEN. MOST GRANDIDIERITES ARE TRANSLUCENT. CUT IN CABOCHON, (CONVEX SHAPE, VERY POLISHED AND WITHOUT FACETS), IT SOMETIMES LOOKS LIKE JADE.