QUARTZ CREEK (RAINY) MINE
near North Bend, King County, Washington, USA
LOCALITY IMAGES


GEOLOGY
Mineralization is associated with intrusion of the Snoqualmie Batholith - late Oligocene to early Miocene (28 Ma[million years ago] to 22 Ma).

Mineralizations occurs in intrusive breccias north of Quartz Creek. Copper was dicovered in 1901 at this site. Exploration and mining operations occured during the early to mid 20th century amd included the development of an approximate 100-foot long horizontal adit (west adit) and two shallow tunnels and a winze driven about 106 feet down into bedrock (east adit) (Northwest Mining Publishers, LLC, 2008).

MINERALS
*Anthophyllite
- Crystals are pseudomorphed to talc.
*Arsenopyrite
- FeAsS - Occurs as subhedral to euhedral grains in massive quartz in outcrops near the west adit.
Brannerite(1)
- Uranium Calcium Titanium Iron Oxide
Chalcopyrite(1)
- CuFeS2
Copper
- Cu - Micro-dendrites of native copper occur in massive quartz.
*Covellite
- CuS - Occurs as small indigo blue/black anhedral grains in outcrops near the east adit.
Pennantite(1)
- Mn5Al(Si3Al)O10(OH)8
Pyrite
- FeS2 - Occurs as massive and small grains.
Pyrrhotite(2)
- Fe(1-x)S
Quartz
- SiO2 - Occurs as terminated crystals to a few centimeters within cavities and massive opaque white grains.
Scheelite(2)
- CaWO4
*Talc
- Mg3Si4O10(OH)2 - Talc pseudomorphs after anthophyllite occur in outcrop near the east adit. The pseudomorphs are tan to light-blue striated prismatic crystals to about 5 cm associated with massive sulfide and tourmaline.
Tourmaline -
Occur as fine black sprays associated with massive sulfide in outcrops near the east adit.

* photographed

1 Cannon, Bart, 1975, Minerals of Washington.
2 Lasmanis, R. et al., 1990, Metal Mines of Washington - Preliminary Report.
 
ARSENOPYRITE in QUARTZ
 
TALC after ANTHOPHYLLITE
with COVELLITE



REFERENCES

Northwest Mining Publishers, LLC, 2008, Discovering Washington's Historic Mines, Volume 1: The West Central Cascade
     Mountains. Pages 180-181.