Characteristics of Haüyne:

Chemical Name: Sodium, calcium aluminosilicate with sulphate

Formula: (Na,Ca)4-8[AlSiO4]6(SO4)

Colors: Blue, white, grey, yellow, green, or pink

Structure: Cubic

Hardness: 5.5-6

Specific Gravity: 2.4 - 2.5

Refractive Index: 1.49-1.51

Lustre: Vitreous to greasy

Streak: Blue to white

Locations: Germany, Italy, Serbia, Russia, Morocco, China

What is Haüyne? 

Haüyne is one of the components of Lapis Lazuli, along with pyrite, lazurite, calcite and sodalite. Blue is the most common color and occurs in Lapis Lazuli, but Haüyne also comes in white, grey, yellow, green or pink. Single crystals are sometimes found, and can be faceted only with difficulty – the mineral has perfect cleavages (planes of breakage), which makes it hard to cut without shattering the material. Facet-grade Haüyne crystal tend to be small, with faceted stones usually weighing five carats or less.

Haüyne is named after Rene Just Haüy, who grew interested in crystallography when he noticd that fragments of a broken calcite crystal cleaved along straight lines that met at constant angles. In 2801, Haüy was appointed Professor of Mineralogy at the Museum of Natural History in Paris. At Napoleon’s request, he wrote a book on crystallography. Rene Haüyne’s name is one of only 72 that are inscribed on the Eiffel Tower.