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Syngenite
Current inventory:  0 gems
 

  
Syngenite is named from the Greek word for related, for the chemical resemblance to polyhalite.

Discovered in 1872.   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

K₂Ca(SO₄)₂•(H₂O)

Hydrated Potasium Calcium Sulfate

Molecular Weight:

328.42. gm

Composition:

Potasium

23.81 %

K

28.68 %

K₂O

Calcium

12.20 %

Ca

17.08 %

CaO

Hydrogen

0.61 %

H

5.49 %

H₂O

Sulfur

19.53 %

S

48.76 %

SO₃

Oxygen

43.85 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Sulfates

Strunz 8th Ed. ID:

6/C.21-60

Nickel-Strunz 10th Ed. ID:

7.CD.35

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H₂O
D : With only large cations

Related to:

None

Varieties:

None

Synonyms:

Kaluszite, Kaluszyt

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

As crystals, tabular on {100} to prismatic along [001], with many forms recorded, to 14 cm; forms lamellar aggregates and crystalline crusts.

Twinning:

Contact twins on {100} common.

Physical Properties

Cleavage:

On {110} and {100}, perfect; on {010}, distinct.

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

2.5

Density:

2.579 - 2.603 (g/cm³)

Luminescence:

None

Radioactivity:

Barely Detectable; GRapi = 343.09 (Gamma Ray American Petroleum Institute Units)

Other:

Soluble in H₂O, with separation of gypsum.

Optical Properties

Color:

Colorless, milky White, faintly Yellow due to inclusions; Colorless in transmitted light.

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.501 - 1.518  Biaxial ( - )

Birefringence:

0.0170

Dispersion:

Very Strong;  r < v

Pleochroism:

None

Occurances

Geological Setting:

An uncommon diagenetic component of marine salt deposits; a volcanic sublimate or pneumatolytic reaction product; a hydrothermal vein filling in a geothermal field; derived from bat guano in caves.

Common Associations:

Halite, Arcanite (salt deposits); Biphosphammite, Aphthitalite, Monetite, Whitlockite, Uricite, Brushite, Gypsum (caves).

Type Locality:

Kalusa Salt deposit (Kalusz), Ivanovo-Frankovsk Oblast', Ukraine

Year Discovered:

1872

View mineral photos:

Syngenite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Syngenite is a typically colorless or white saline evaporite mineral composed of hydrous potassium calcium sulphate and occurring in tabular crystals. Crystals are rarely transparent or translucent enough for faceting as they are typically mostly opaque from impurities. These impurities also often color the crystals faintly yellowish or pinkish brown. Faceted gems are vary rare and really only faceted as a collector odity.

Syngenite is found at several locations worldwide. In Ukraine, large crystals from the Kalush salt deposit (Kalusz, Poland), and at Stebnyk. In Germany, from Thuringia, in the Glückauf mine, near Sondershausen, from Bischofferode, and at Volkenroda-Pöther, near Mühlhausen; from the Stassfurt salt district, Saxony-Anhalt; in the Sigmundshall mine, Bokeloh, and at the Kalkberg, near Lüneburg, Lower Saxony. On Vesuvius, Campania, and in the Cesano geothermal field, Latium, Italy. From Haleakala volcano, Maui, Hawaii, USA. In Murra-el-elevyn, Dingo Dongo, and Petrogale Caves, Western Australia. From Gcwihaba Cave, 280 km west of Maun, northwestern Botswana. On volcanoes on the Kamchatka Peninsula, Russia. Around Mt. Erebus, Victoria Land, Antarctica. From the “Q” Basin [Jianghan Plain] potash deposits, Hubei Province, China.
 

  
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