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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Jacobsite from
Jail Hill Road locality (Jail Hill Quarry), Haddam, Middlesex County, Connecticut, USA


09102000017390482853509.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
09174840017272020384293.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
09102000017390482853509.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
09174840017272020384293.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
09102000017390482853509.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
09174840017272020384293.jpg
Jacobsite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
Classification
Species:Jacobsite
Formula:Mn2+Fe23+O4
Comments:"Specimens of tephroite from the Jail Hill quarry contain magnetic grains, shown (by X-ray and microprobe study at the University of Michigan) to be jacobsite. The material ranges from ferroan jacobsite to manganoan magnetite, within individual grains. A few specimens show it rather abundantly."
Specimens are in the Harvard Mineralogical Museum.
Quality for species:Poor for species, only of interest for locality collectors. (#)
Abundance at site:Rare
Confirmation
Validity:Confirmed
Confirmation Methods:XRD
Associated Minerals Based on Photo Data:
Tephroite2
Quartz1
Microcline1
- var Hyalophane1
Data
Mineral Data:Click here to view Jacobsite data
Locality Data:Click here to view Jail Hill Road locality (Jail Hill Quarry), Haddam, Middlesex County, Connecticut, USA
Photo GalleryView Gallery (2 photos)
Data Identifiers
Mindat Occurrence Record ID:130241
Long-form Identifier:1:3:130241:7
GUID (UUID V4):0
References
Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
 
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