Shortite
Current inventory:  1 gem
 

  
Shortite is named after Maxwell Naylor Short (1889 - 1952), professor of mineralogy, University of Arizona, Tucson, USA.

Discovered in 1939;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Na₂Ca₂(CO₃)₃

Sodium Calcium Carbonate

Molecular Weight:

306.16 gm

Composition:

Sodium

15.02 %

Na

20.24 %

Na₂O

Calcium

26.18 %

Ca

36.63 %

CaO

Carbon

11.77 %

C

43.12 %

CO₂

Oxygen

47.03 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Carbonates

Strunz 8th Ed. ID:

5/B.05-70

Nickel-Strunz 10th Ed. ID:

5.AC.25

5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H₂O
C : Alkali and alkali-earth carbonates

Related to:

Eitelie - Shortite - Carbocernaite Series

Crystal Data

Crystallography:

Orthorhombic - Pyramidal

Crystal Habit:

Crystals are typically wedge-shaped, tabular to short prismatic, to 3 cm, striated.

Twinning:

None

Physical Properties

Cleavage:

[010] Distinct/Good

Fracture:

Conchoidal

Tenacity:

Brittle

Hardness (Mohs):

3.0 - 4.5

Density:

2.600 - 2.629 (g/cm³)

Luminescence:

Pale amber fluorescence under SW UV

Radioactivity:

Not Radioacitve

Other:

Strongly Pyroelectric. Water Soluble; decomposed by water with separation of CaCO3.

Optical Properties

Color:

Colorless, light Yellow, dark Yellow, light Green

Transparency:

Transparent

Luster:

Vitreous

Refractive Index:

1.531 - 1.570  Biaxial ( - )

Birefringence:

0.0390

Dispersion:

Moderate; r < v

Pleochroism:

X = colorless, Y = colorless, Z = colorless

Occurances

Geological Setting:

In saline dolomitic marl (Green River Formation, Wyoming and Utah, USA); in kimberlite dikes (Upper Canada mine, Canada); in carbonatite (Vuoriyarvi massif, Kola Peninsula, Russia); in differentiated alkalic massifs (Kovdor and Khibiny massifs, Kola Peninsula, Russia); associated with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada).

Common Associations:

Nahcolite, Pyrite, Trona (Green River Formation, Wyoming and Utah, USA); Apatite, Calcite, Magnetite, Olivine, Perovskite, Phlogopite (Upper Canada mine, Canada); Albite, Barentsite, Natrite, Natrolite, Villiaumite (Khibiny massif, Kola Peninsula, Russia)

Type Locality:

John Hay Jr. Well No. 1, Green River Formation, Sweetwater Co., Wyoming, USA

Year Discovered:

1939

View mineral photos:

Shortite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

According to the Color Encyclopedia of Gemstones by Joel Arem, "Shortite is an exceedingly rare mineral. Cut gems are among the rarest of all faceted stones. The material is a carbonate and is therefore fragile and soft." The mineral ranges from colorless to pale yellow. Shortite was first described by J.J. Fahey of the U.S. Geological Survey as a new mineral in 1939. It was discovered in oil well drill cores from the Green River Formation in Wyoming and Utah. Yellow crystals of Shortite were discovered at Mont Saint-Hilaire, Québec, Canada in 1991, and small gems were faceted from transparent pieces. Shortite is soft and fragile, with a perfect cleavage and the large birefringence typical of a carbonate mineral. The fact that it decomposes in water makes it very difficult to facet.
 

  
Shortite gems for sale: