Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite
Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
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Gahnite from
Chrysoberyl locality, Haddam, Middlesex County, Connecticut, USA


Locality type:Outcrop
Classification
Species:Gahnite
Formula:ZnAl2O4
Comments:Referred to by Shepard (1837) as "automolite". Crystals up to 1 inch (Silliman, 1829). Apparently more common than the columbite-(Fe).
Habit:massive grains, subhedral octahedrons
Colour:dark bluish green
Abundance at site:Rare
Confirmation
Validity:Believed Valid
Associated Minerals Based on Photo Data:
Chrysoberyl1
Albite1
Data
Mineral Data:Click here to view Gahnite data
Locality Data:Click here to view Chrysoberyl locality, Haddam, Middlesex County, Connecticut, USA
Data Identifiers
Mindat Occurrence Record ID:660290
Long-form Identifier:1:3:660290:1
GUID (UUID V4):0
Nearest other occurrences of Gahnite
0.6km (0.4 miles) ⓘThulite locality, Haddam, Middlesex County, Connecticut, USA
1.4km (0.9 miles) ⓘTimms Hill (Tim's Hill; Iolite Hill), Haddam, Middlesex County, Connecticut, USA
10.8km (6.7 miles) ⓘGreat Hill cobalt mines, Cobalt, East Hampton, Middlesex County, Connecticut, USA
13.4km (8.4 miles) ⓘStrickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA
13.9km (8.6 miles) ⓘPelton's Quarry, Portland, Middlesex County, Connecticut, USA
17.8km (11.1 miles) ⓘNike prospect, Portland, Middlesex County, Connecticut, USA
18.5km (11.5 miles) ⓘSimpson Quarry (Wiarda Quarry), South Glastonbury, Glastonbury, Hartford County, Connecticut, USA
18.7km (11.6 miles) ⓘHollister prospects, South Glastonbury, Glastonbury, Hartford County, Connecticut, USA
References
Silliman, Benjamin. (1829): Discovery of Columbite in Chesterfield, Mass. American Journal of Science, s. 2, vol 16. pp. 220-224.
Shepard, Charles Upham (1837) A Report on the Geological Survey of Connecticut. Geological Survey of Connecticut.
 
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