Derrick Cave – Fort Rock, Oregon

Derrick Cave is a large lava tube, located in south-central Oregon. The cave is best accessed from the north. Original access was described as part of the BLM’s Back Country Byway. However, this route requires crossing private land. The current landowners appear to have had enough bad experiences with people not understanding how to drive on rocky, gravel roads. Signs posted at the start of their property warn that there is no longer access to Derrick Cave from the south. A good forest service map of the Newberry National Monument will lead you to the cave.

Derrick Cave is unique in both its size (30-foot diameter) and use as a nuclear fall-out shelter during the Cold War. At one time, the cave was outfitted to provide food and water for approximately 1,200 people.

Our visit to Derrick Cave was the first ‘caving’ experience for me and my son. It was a great way to start our caving adventures. The cave is big enough that we were able to stand throughout. The hiking involved a bit of scrabbling across boulders. The biggest adjustment was hiking in the dark. We had some fun with periodically turning all of our lights off.

We brought a few head lamps, flashlights and our usual first aid kit and water. We spent about an hour hiking into and out of the cave. Because it was spring, the outside temperature was not much different from the interior of the cave. However, in the summer, the temperature difference would be large. There are ice formations in the cave. There was also quite a bit of dust. The surfaces of the rocks are abrasive – so long sleeves, gloves and good shoes (i.e. not flip-flops) are a good idea. I walked out with torn gloves, but my running shoes were fine.

Dust Devil Mining - Digging for Sunstones

The Oregon gemstone is the sunstone - a plagioclase feldspar - containing copper shiller. A designated public sunstone collection area is found in the Rabbit Basin to the northwest of the Hart Mountain Antelope Refuge.

We have a family interest in rocks and have enjoyed looking for thundereggs at Richardson Rock Ranch in Madras and fossils in Fossil. We visited Dust Devil Mining to collect sunstones. The people at Dust Devil Mining were really helpful and led us through all of the ways to find sunstones. The mine included options to  dig, rake, sift and pick rocks apart - looking for sunstones. This is a terrific activity for youngsters. The rocks are easy to find.

Oregon Rocks

We just returned from a trip to the John Day Fossil Beds Monument. The monument is located in the north-central part of the state of Oregon; about a 5-hour drive from Portland. We like to visit this location because:

- it is a beautiful part of Oregon
- there are not many people
- we like fossils and rocks

On the way out, we stopped in Madras at the Richardson Rock Ranch to hunt and dig for thundereggs. The ranch is quite large (of 20 square miles) and has been in the family for 7 generations. In addition to cattle ranching, the Richardson family allows people to hunt for a variety of rocks. They also sell rocks from around the world.

At first, we had no idea what we were doing. We drove to an area set-up for digging and pulled out our gloves, eye protection and borrowed rock hammers (provided at the ranch). The gloves and eye protection were great to have. Towels and water would have been good, too. Digging was a dusty process.

A knowledgable fellow showed up with his family and helped us to better understand what we were looking for. Thundereggs can have ridges on the outside that indicate the formation of a central agate region that is usually fairly crystalline in appearance. There are also mudballs that contain a lot of small round nodules on the outside and a fairly dense, dark center.  We picked up about 10 pounds of rocks - mostly thundereggs, but also a piece of obsidian and some rose quartz.

We will have to go to the Rice Museum and see if we can have the thundereggs cut open.

In terms of a family event - this was a great way to go. We could have spent the entire day at the ranch - especially if we had brought a lunch. There are several digging sites and the store and museum of interesting. Our son's imagination was running free while we were digging. He formed a rock-hounding partnership with another little boy and they were busy the entire time.

It would be helpful to do some research beforehand to know more about what to look for.