MORGANITE

    Class : Silicates
    Subclass : Cyclosilicates
    Crystal system : Hexagonal
    Chemistry : BeAl2Si6O18
    Rarity : Common

Morganite is a pink-colored gem variety of beryl, originally described in the Californian pegmatites of San Diego County and named after the American financier and mineral collector J.P. Morgan. It is a beryl rich in alkalis (cesium, lithium, rubidium, etc...) characterized by a tabular development of hexagonal crystals, and which is found in sodolithic pegmatites, accompanied by other lithium minerals (elbaite, lepidolite). It is widely used in jewelry.

Main photo : Morganite and quartz from Laghman, Afghanistan © Kevin Ward

Morganite from Carmelita Mine, San Diego, California, USA © Scott L. Ritchie
Morganite from Rubelita, Minas Gerais, Brazil © Kuno Stoeckli
26.07 ct pear faceted morganite from Brazil
Morganite from San Piero in Campo, Island of Elba, Italy © Matteo Chinellato

Morganite in the World

The most extraordinary specimens come from the Brazilian pegmatites of Minas Gerais (Corrego do Urucum near Galiléia, Conseilhero Pena...) where entirely gemmy crystals of more than 25 cm in diameter and a weight exceeding 25 kg were discovered. Still in Minas Gerais, we must highlight the original green crystals with a pink center measuring 10 cm in diameter from Rubelita. The morganites from Madagascar (Anjanabonoina and Maharitra) are famous for their delicate pink hue, those from California (Pala and Mesa Grande) for the magnificent compositions that the 7 cm diameter crystals create with elbaite prisms and cleavelandite. The pegmatites from Muiâne (Mozambique) gave very large crystals (40 cm) but of poor quality. Finally, the pegmatites of Nuristan (Afghanistan) also produce magnificent crystals while in Europe, morganite is present in San Piero, on the island of Elba (Italy) in crystals no larger than 3 cm.

Morganite in France

Morganite is not known in the French underground.

Twinning

No twin known for this mineral species.

Fakes and treatments

Because of its interest in jewelry, morganite is commonly treated by irradiation to modify the color or heated to reduce the yellow and therefore make it more pink. These treatments are very difficult to detect, even in the laboratory.


Hardness : 7.5 to 8
Density : 2.63 to 2.92
Fracture : Conchoidal
Streak : White

TP : Translucent to transparent
RI : 1.568 to 1.602
Birefringence : 0.005
Optical character : Uniaxial -
Pleochroism : Visible
Fluorescence : Sometimes blue

Solubility : Hydrofluoric acid, sodium hydroxide

Magnetism : NoneRadioactivity : None