Tunk Creek: Quartz & Blue Corundum Rockhounding in Okanogan County, Washington
Updated June 2026
Tunk Creek is one of Washington's few documented thulite localities, where rose-pink thulite, a variety of zoisite, occurs in lenses up to three feet across within hornblende schist. The same schist hosts corundum, including blue sapphire and pink to red crystals associated with the thulite, an unusual pairing recorded by the USGS Mineral Resources Data System and mindat. Quartz and plagioclase round out the assemblage in the Okanogan highlands. Reported finds include quartz, blue corundum, pink corundum, thulite, plagioclase. Below: coordinates, access notes, nearby spots, and trip-planning links.
Tunk Creek photos
Public image records connected to this spot or its reported material.
Map showing Tunk Creek in Okanogan County, Washington
Quick details
- Access
- Public area
- County
- Okanogan County
- State
- Washington
- Nearest road
- Keystone Road
- Coordinates
- 48.56146, -119.48658
Geology at Tunk Creek
This spot sits on continental glacial drift, Fraser-age; mostly Vashon Stade in western WA; unnamed in eastern WA, mapped as sand and gravel that formed within roughly the last 3 million years. Loose deposits like these are float-collecting ground: erosion keeps moving durable rocks and minerals into gravel bars, cutbanks, and washes.
- Mapped unit
- continental glacial drift, Fraser-age; mostly Vashon Stade in western WA; unnamed in eastern WA
- Age
- 3 Ma to present (Pleistocene)
- Rock types
- sand and gravel
- Elevation
- 860 ft
Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.
Best time to visit Tunk Creek
Best months: March to June. Typical highs run 91°F in midsummer and 34°F in midwinter, with winter lows near 25°F.
Climate normals: NOAA 1991-2020 monthlies, OMAK station (7 mi away), adjusted for elevation.
Land & collecting status
Generally open to casual rockhounding
Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.
Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.
Sources & verification
Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.
State guidance last verified:
- Washington Geological Survey (DNR)
- Stonerose Interpretive Center — Visit & rules
- BLM Spokane District
- Community submissions reviewed against published agency rules
Found at Tunk Creek
Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.
Nearby rockhounding spots
Other rockhounding spots within driving distance of Tunk Creek.
- Lyman LakeOkanogan County, Washington · 21 mi awayGold, Quartz
- Osoyoos LakeOkanogan County, Washington · 28 mi awayCopper, Pyrite
- Mary Ann CreekOkanogan County, Washington · 32 mi awayGold
- Gold CreekFerry County, Washington · 32 mi awayGold
- MethowOkanogan County, Washington · 33 mi awayStibnite, Chalcopyrite
- BridgeportDouglas County, Washington · 40 mi awayJadeite
- Nespelem to Coulee DamDouglas County, Washington · 43 mi awayGold
- Cathedral PeakOkanogan County, Washington · 43 mi awayWolframite
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