Sapir is deep-blue lazurite.
The ancient Hebrew gem name Sapir ספיר signifies the mineral that today English calls lazurite. The identity is confident. (Klein.) Lazurite has a crystalline structure but rarely crystallizes well. Thus its opaque blue tends to aggregate with other minerals, especially white calcite and goldlike pyrite.
Often azure encompasses cloudy wisps and starry gleams to physicalize the celestial splendor of the skies above.
(Vere. ©2011. "Sapir Aggregate".)
The mineral crystalizes, ideally, according to the following chemical formula:
(Na, Ca)8 (Al6 Si6 O24) (S, SO4, Cl2). (Hassan.)
(Vere. ©2011. "Sapir Crystal".)
Today jewelers reserve term lazurite for pure glassy crystal and the term lapis lazuli for opaque aggregate rock.
But the ancient term Sapir specifies the mineral lazurite, whether pure or aggregate. The deeper the blue the better. “Deep” means the color is dark-but-intense. The brilliant blue hue saturates the color, shining in shadow. It evokes twilight sky, when dusk turns azure.
Sapir is “the” stone of heavens.
• (Vere, Stein Atle. ©2011. "Sapir Aggregate". Derivation. Anonymous Luna04. 2005 share alike. Wikipedia. http://en.wikipedia.org/wiki/File:Lapis_lazuli_block.jpg, 2011.)
• (Vere, Stein Atle. ©2011. "Sapir Crystal". Derivation. Lavansky, Rob. 2005 share alike. Wikipedia. http://en.wikipedia.org/wiki/File:Lazurite-177793.jpg, 2011.)
• (Klein, Earnest. ©1987. “סַפִּיר”. A Comprehensive Etymological Dictionary of the Hebrew Language for Readers of English. New York: Macmillan Publishing Company.)
• (Hassan, I & Peterson, RC & Grundy, HD. ©1985. “The structure of lazurite, ideally Na6Ca2(Al6Si6O24)S2, a member of the sodalite group”. Acta Crystallographica. C41: 827-832.)