VESPER PEAK SKARN
Snohomish County, Washington, USA

LOCALITY IMAGES


GEOLOGY
Skarn Deposit, periphery of tonalite exposed on Vesper Peak (Squire Creek stock) - Oligocene (between 33.9 million to 23 million years before the present). The skarn deposit resulted from contact metasomatism of a limestone pod in Jurassic age sedimentary rock (predominately ribbon chert) adjacent to the tonalite intrusion.

MINERALS (incomplete list) CLICK for COMPLETE LIST
*Calcite -
CaCO3 - Occurs as flattened white rhombohedral crystal. Quartz epimorphs after calcite have been found.
*Clinozoisite -
Ca2Al3(SiO4)3(OH) - Occurs as gemmy honey-yellow prismatic crystals, some with parallel twinning.
*Ferro-axinite -
(Ca,Fe,Mn)3Al2BO3Si4O12OH -
*Garnet (var. grossular) -
Ca3Al2(SiO4)3 - Occurs as lustrous green to orange dodecahedral crystals with some crystals exhibiting cube faces. Crystals to over 2.5 cm have been found.
*Hedenbergite (Ca,Fe pyroxene) -
CaFe2+(Si2O6) - Occurs as green to black crystals reported up to 8 cm in length (Cannon, 1991). Electron microprobe analyses completed by Cannon of Vesper Peak pyroxenes suggest all color varieties fall within the hedenbergite compositional range.
*Prehnite -
Ca2Al(AlSi3O10)(OH)2 - Occurs as light green to white clustered fan-like sheaths with individual crystals to about 4 cm. The prehnite is typically etched.
*Titanite -
CaTiSiO5 - One pocket contained loose gemmy honey-colored crystals to about 2 cm long.

* photographed
 
HEDENBERGITE

 
CLINOZOISITE
Photo Copyright Saul Krotki 2007

 
CLINOZOISITE, HEDENBERGITE,
GROSSULAR garnet
John Lindell Collection

 
GROSSULAR garnet

 
GROSSULAR garnet
John Lindell Collection

 
AXINITE with GROSSULAR garnet
John Lindell Collection

 
PREHNITE with HEDENBERGITE
John Lindell Collection

 
PREHNITE

 
QUARTZ epimorph after CALCITE
John Lindell Collection

 
GROSSULAR garnet on QUARTZ
John Lindell Collection

 
Gemmy TITANITE
John Lindell Collection




REFERENCES

Cannon, Bart, (November-December 1991) The Vesper Peak Garnet Deposit, Snohomish County, Washington. Rocks & Minerals. 66(06), 478-484.