Lapis lazuli

Big Photo

Afghanistan
444.55 carats
© gemselect.com

Lapis Lazuli (Arabic and Latin - blue stone) can be described as an impure variety of the mineral Lazurite, however more accurately it is a type of rock containing primarily Lazurite (25-40%), Calcite and Pyrite (also augite, diopside, enstatite, mica, hornblende, sodalite, haüyne).

It has a very distinctive blue colour (due to the Lazurite). Too much pyrite causes a dull, greenish tint. In the best-quality specimens, the colour is evenly distributed, but in general it is spotty or striated.

As well as use in carvings and gems, it has been used for millennia as a blue pigment when ground to a fine powder (known as ultramarine).

Lapis lazuli Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 

Lapis lazuli Gemstones by Size

This table shows distribution of Lapis lazuli gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:3.57 cts
Heaviest:444.55 cts
Average:28.10 cts
Total photos:47
Do you have a larger Lapis lazuli? Why not upload a photo?
3.57ct to 47.67ct47.67ct to 91.77ct91.77ct to 135.86ct135.86ct to 179.96ct179.96ct to 224.06ct224.06ct to 268.16ct268.16ct to 312.26ct312.26ct to 356.35ct356.35ct to 400.45ct400.45ct to 444.55ct
General Information
A variety or type of:Lazurite, which is a variety of Haüyne
Chemical Formula
(Na,Ca)
 
8
[(SiO
 
4
,S,Cl)
 
2
I(AlSi)
 
4
]
 
6
Walter Schumann, Gemstones of the world (2001)
Photos of natural/un-cut material from mindat.org
Lapis lazuli Treatments
Heating to red heat has been reported (Bauer, 1968) to intensify the color of some pale blue lapis lazuli to yield a fine, dark blue, but this may produce an unattractive greenish blue in some specimens.
Dyeing, often using aniline dyes, is frequently practiced to improve the color of lapis lazuli, although even almost colorless material has been so treated (Crowningshield, 1967). Coloring for the disguising of white calcite inclusions is also done. Localization of the color in cracks can usually be seen, and a cotton swab soaked in acetone or nailpolish remover usually reveals the dye. This may not work, however, if a colorless wax has been used as a final step, in which case it must first be rubbed off (Crowningshield, 1968; Fryer, 1981); the wax is revealed by a hot-point examination. The colorless wax is apparently intended to hide cracks, improve the surface polish, as well as to prevent the dye from rubbing off onto clothes or skin.
The use of colored waxes (including blue shoe paste!) has also been reported (Crowningshield, 1965) – Nassau (1984)

Often impregnated with wax or oil. Dyed: Calcite masked. Streak: dark blue (if not coated). Diluted acid test (acetone usually not conclusive) - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Lapis lazuli Simulants
Common imitations: dyed magnesite, dyed jasper, dyed howlite, sodalite - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Physical Properties of Lapis lazuli
Mohs Hardness5.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity2.50 to 3.00
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Cleavage QualityIndistinct
Walter Schumann, Gemstones of the world (2001)
FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Lapis lazuli
Refractive Index1.500 to 1.670
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
BirefringenceNone
Walter Schumann, Gemstones of the world (2001)
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
DispersionNone
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Lazur blue, violet, greenish-blue
Walter Schumann, Gemstones of the world (2001)
More from other references
TransparencyOpaque
Walter Schumann, Gemstones of the world (2001)
LustreVitreous,Greasy
Walter Schumann, Gemstones of the world (2001)
Fluorescence & other light emissions
Fluorescence (General)Strong: white, also orange, copper-coloured
Walter Schumann, Gemstones of the world (2001)
Fluorescence (Short Wave UV)May show a pinkish response
Michael O’Donoghue, Gems, Sixth Edition (2006)
Fluorescence (Long-Wave UV)Orangy to pinkish spots (calcite)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Crystallography of Lapis lazuli
Crystal SystemIsometric
Walter Schumann, Gemstones of the world (2001)
HabitRare; dense aggregates
Walter Schumann, Gemstones of the world (2001)
Geological Environment
Where found:Occurs mainly in association with leucite or nepheline in nepheline syenites, phonolites and related undersaturated igneous rocks.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Inclusions in Lapis lazuli
Pyrite inclusions, spots and veins of calcite - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Further Information
Mineral information:Lapis lazuli information at mindat.org
Significant Gem Localities
Afghanistan
 
  • Badakhshan Province (Badakshan Province; Badahsan Province)
    • Khash & Kuran Wa Munjan Districts
      • Koksha Valley (Kokscha Valley; Kokcha Valley)
        • Sar-e Sang (Sar Sang; Sary Sang)
Bowersox and Chamberlin (1995)
Chile
 
  • Coquimbo Region
    • Limarí Province
      • Ovalle
Ward (1996)
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Bernardmyo
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Chaung-gyi
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
        • Kyatpyin North
Ted Themelis (2008) Gems & mines of Mogok
        • Kyauk-Pyat-That
Ted Themelis (2008) Gems & mines of Mogok
        • Marble Ark
Ted Themelis (2008) Gems & mines of Mogok
        • Mogok Valley
          • Dattaw-taung (Dattaw hill)
            • Dattaw-mid
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Russia
 
  • Eastern-Siberian Region
    • Prebaikalia (Pribaikal'e)
      • Irkutskaya Oblast'
Spiridonov (1998)
Tajikistan
 
  • Viloyati Mukhtori Gorno-Badakhshan (Viloyati Badakhshoni Kuni)
Spiridonov (1998)
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