Polka Dot Agate Mine: Home to Distinctive Agates and Giant Thundereggs

Priday Polka Dot Agate Mine is a famous location that produces unique agates with polka-dot pattern of contrasting colors, "Blue Ice" agate, and large thundereggs. The mine is located 25 miles northeast of Madras and managed by West Coast Mining Company.

Polka Dot Agate is an orbicular agate with a fan pattern of multicolored oval inclusions or dots. The size of dots varies from slightly visible to one-quarter of an inch. The translucent to opaque Polka Dot agate features white, creamy, or blue base with brown, golden-yellow, and orange dots.

Some dots are fully agatized, while others consist of iron (brown) or manganese (black) oxide dendrites. Certain specimens also feature black dendrites and patches of brown jasper within their translucent sections.

Another notable material is the light-blue agate known as "Blue Ice" or "Blue Ice Ocean", highly valued by lapidarists and collectors for its quality. Polka Dot and Blue Ice cut cleanly and take an excellent high-gloss polish.

The main agate bed lies in the canyon just below the parking area. Although digging is currently closed to the public for safety reasons, visitors can still walk to the canyon floor and view the exposed seams of agate along the hillside.

Mining at this site dates back thousands of years. Native Americans collected agate here to make sharp tools such as knives, arrowheads, and spears, and several of their hand-dug tunnels remain visible along the right side of the hill.

In addition to agates, there is a thunderegg deposit at the Polka Dot Agate Mine. Canyon Rim Thunderegg Bed produces large and interesting specimens. Check with the mine office if it is open for public digging.

The Polka Dot shop offers a wide range of rocks and minerals for purchase, including local Polka Dot agates, as well as picture jasper, thundereggs, and green jasper from other mines, operated by West Coast Mining.

The mine is open seasonally, typically, from Memorial Day to Labor Day. Sometimes, the entrance near the Polka-dotted trailer can be closed, which means the operation is shut down for this day. It is advisable to contact the mine before making a long trip to confirm if it is open.

Richardson's Rock Ranch, known for its extensive world-famous deposits of mineral-filled nodules or thundereggs, is located just 14 miles away of the mine. Besides local rocks, the ranch's rock shop offers for sale varieties of specimens from all over the world.

Cove Palisades State Park and Lake Billy Chinook, 34 miles west of Polka Dot, is a great place for fishing, boating, swimming, and hiking.

Situated 47 miles southwest, Smith Rock State Park features a ridge with the highest promontory at 3,200 feet rising over the Crooked River Canyon. It is a popular site for rock climbers.

Peter Skene Ogden Wayside is a dramatic 300-foot-deep canyon into the Crooked River Gorge, featuring a stunning view, walking trails with interpretive panels, picnic areas, and bungee jumping. It is located 48 miles southwest on Highway US 97.

Kah-Nee-Ta Resort & Spa, 46 miles northwest, is a remote hot spring oasis hidden in the high desert.