Lazulite Value, Price, and Jewelry Information

Mixed oval-cut lazulite, 1.26 cts, 7.6 x 5.9 mm, Pakistan. © The Gem Trader. Used with permission.

Lazulite

Lazulite makes a magnificent, deep blue gemstone. Although the mineral itself occurs widely, gem-quality rough is limited. Specimens are prized by collectors but can also be faceted with care or cut into cabochons for jewelry.

Lazulite Information

Data Value
Name Lazulite
Crystallography Monoclinic; crystals acute pyramidal; massive, compact, granular.
Refractive Index Varies by series member, 1.604-1.680. See “Identifying Characteristics” below.
Colors Blue, blue-green, light blue, deep azure blue.
Luster Vitreous to dull
Hardness 5.5-6
Fracture Uneven
Specific Gravity 3.08-3.38. See “Identifying Characteristics” below.
Birefringence Varies by series member, 0.031-0.040. See “Identifying Characteristics” below.
Cleavage Indistinct to good, 1 direction
Luminescence None
Luminescence Present No
Transparency Transparent to opaque
Absorption Spectrum Not diagnostic
Formula (Fe,Mg)Al­2(PO4)2(OH)2
Pleochroism Strong: colorless/blue/dark blue.
Optics Biaxial (-). See “Identifying Characteristics” below.
Optic Sign Biaxial -
Etymology From the German lazurstein, meaning “blue stone.” Scorzalite is named after E. P. Scorza, a Brazilian mineralogist.
Occurrence Quartz veins; granite pegmatites; metamorphic rocks, especially quartzites.
Inclusions Healed fractures, feathers, single and two phase liquid and gas inclusions.
lazulites - Canada

Lazulites on limonite matrix, 7.8 x 5.3 x 1.5 cm, Mt. Seafoam, Rapid Creek, Yukon, Canada. © Rob Lavinsky, www.iRocks.com. Used with permission.

Comments

Although lazulite’s hardness of 5.5 to 6 makes it a marginal choice for jewelry use, lapidaries have cut cabs from massive material, such as that found in New Hampshire or California. Clean stones over 5 carats are extremely rare. Even small gems tend to be extremely included, thus making lazulites susceptible to fracturing during cutting.

Faceted lazulite strongly resembles blue apatite. Other common mistaken identifications for this gem include azurite, turquoise, and blue tourmaline and topaz. Furthermore, lazulite not only resembles lapis lazuli, its name comes very close to “lazurite.” Lazurite is one of the components of lapis lazuli rocks but has no relation to lazulites.

lazulites - cabochons

Lazulite cabochons. Photo by pensondesignergems. Licensed under CC By 2.0.

Identifying Characteristics

The lazulite mineral group includes the lazulite and scorzalite species. These form a solid-solution series: (Fe,Mg)Al2(PO4)2(OH)2. Lazulite is the magnesium member; scorzalite is the iron member. These gems show the same colors and strong trichroic pleochroism. However, their specific gravity (SG) and optical properties vary with their Fe/Mg ratio.

Property

Lazulite (Mg)

Mg½Fe½

Scorzalite (Fe)

SG

3.08

3.22

3.38

Optics:
a

1.604-1.625

1.626

1.627-1.639

β

1.633-1.653

1.654

1.655-1.670

γ

1.642-1.662

1.663

1.664-1.680

Sign

(-)

(-)

(-)

2V

69°

62°

Birefringence

0.031-0.036

0.037

0.038-0.040

Lazulite has a white streak. Many common gemstones have a white streak, too. However, natural lapis lazuli should have a light blue streak. Please note: don’t conduct streak testing on finished gems. Test material in inconspicuous spots as a last resort only.

scorzalite

Scorzalite crystals on matrix, Estano Orcko mine, Machacamarca District (Colavi District), Cornelio Saavedra Province, Potosi Department, Bolivia. © Rob Lavinsky, www.iRocks.com. Used with permission.

Sources

While scorzalite is a relatively rare mineral, lazulite is more abundant. Champion Mine, Mono County, California produces masses up to 6 inches across. Rapid Creek, Yukon, Canada yields fine, gemmy crystals.

Other notable gem-quality localities include:

  • Bhandara district, India: gemmy crystals (RIs 1.615/1.635/1.645; SG = 3.17).
  • Minas Gerais, Brazil: fine blue gemmy crystals; a = 1.604-1.629; β = 1.628-1.655; γ = 1.638-1.666; birefringence = 0.031-0.037; SG = 3.07-3.24.
  • United States: Graves Mountain, Georgia; Palermo Quarry North Groton, New Hampshire; South Dakota.
  • Lobito Bay, Angola; Potosi, Bolivia; Madagascar; Pakistan; Horrsjoberg, Sweden.

Stone Sizes

Faceted gems usually range from 0.5 to 2 carats. Anything larger, especially clean, is extremely rare. The large masses from California aren’t clean enough to facet.

Care

Store lazulite gems and jewelry separately from more commonly encountered gemstones, such as garnet, quartz, topaz, etc. Contact with these harder stones as well as common objects like a steel file could scratch lazulites. Use protective settings for ring use. To clean, use a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more recommendations.

lazulite - faceted

Lazulite: Brazil (0.70, 0.44). Photo © Joel E. Arem, PhD, FGA. Used with permission.

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