Denny Mt.: Calcite & Quartz Rockhounding in King County, Washington

Quick details

Access

Permission required

County

King County

State

Washington

Nearest road

Denny Creek Trail

Postcode

98068

Coordinates

47.43324, -121.44863

Geology at Denny Mt.

This spot sits on Snoqualmie Batholith, mapped as granite that formed roughly 23 to 5 million years ago. Plutonic rock like this weathers slowly into grus and boulders, and the most productive collecting is typically in weathered zones and drainages.

Mapped unit

Snoqualmie Batholith

Age

23–5 Ma (Miocene)

Rock types

granite

Elevation

4,130 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.

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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: April 1, 2026

• Washington Geological Survey (DNR)
• Stonerose Interpretive Center — Visit & rules
• BLM Spokane District
• Community submissions reviewed against published agency rules

Found at Denny Mt.

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

• CalciteEncyclopedia →
• QuartzEncyclopedia →
• AmethystEncyclopedia →
• OpalEncyclopedia →
• PyriteEncyclopedia →