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
*Augite (Ca,Mg, Fe pyroxene) -
CaFe2+(Si2O6) - Occurs as black crystals reported up to a few centimeters (Cannon, 1991).
*Clinozoisite -
Ca2Al3(SiO4)3(OH) - Occurs as gemmy honey-yellow prismatic crystals, some with parallel twinning.
*Garnet (var. grossular) -
Ca3Al2(SiO4)3 - Occurs as lustrous 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 dark green crystals reported up to 8 cm in length (Cannon, 1991).
*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.

* photographed
 
AUGITE

 
CLINOZOISITE
Photo Copyright Saul Krotki 2007

 
Grossular GARNET

 
PREHNITE




REFERENCES

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