Here’s an idea for you frustrated rockhounds that are looking for a cool summer collecting spot close to the Los Angeles area. This one is high on a ridge in the Angeles National Forest at the 7,000 foot level. The object of this outing is actinolite. It is noted for its lustrous bladed green crystals that often form fan shapes. This amphibole derives its green coloration from the presence of lead in its chemical composition.
We used Wrightwood as the jump-off point for our trip. While you are having breakfast downtown, look westward at the ridge. There is an obvious barren scarp that was caused by the huge mud flow that roared down from that spot in 1941. The bedrock in this section of the San Gabriels is pre-cambrian pelona schist, consisting of a large variety of metamorphic rocks, among them actinolite. The nearby San Andreas fault, and the weathering caused by winter freezes, built up a huge amount of talus that provided the bulk of the material that slid down 5,000 feet and traveled fifteen miles into the desert! It is possible to comb the debris in Heath Canyon and Sheep Creek for pieces of actinolite, but we are going to go up to that ridge and hopefully find some specimens in a bit better condition!
From Wrightwood travel east for about four miles on Highway 2 to the Big Pines Recreation Area. You will turn left here, continuing on Highway 2. If you don’t already have a Forest Adventure Pass you will want to pick one up at the Ranger Station here because they are required to park a vehicle within the forest boundary. Continue up Highway 2 for 1.8 miles to the signed Inspiration Point turn off on your left. From here you will take the road to Blueridge Campground. This road becomes graded dirt, but is no problem for the typical family car. You will continue on it through Blueridge Campground and on to Guffy Campground, a total of about five miles. We parked at Guffy, hung our Adventure Pass on the rearview mirror, shouldered our backpacks and water bottles, and hiked through the locked gate barring the ridge road from Guffy eastward. If the gate is unlocked, which is unlikely in the summer, then instead of stopping at Guffy you can drive to the collecting site! After hiking about four-tenths of a mile, the Prairie Fork road will branch off and descend to your right. The views here are marvelous. High to your right is the back side of Mount Baldy, and down to your right is a beautiful valley and the Native Son Mine. Jays and gray squirrels punctuate the quiet, pine scented air. Now, if we can just find some actinolite everything will be perfect! You’ve got about another mile to hike from this junction before you reach the collecting area. If you reach a forestry trail marker you have gone far enough, and you will want to stop and try collecting on either side of the road back the way you came. We had the most success right at the edge of the road. In fact we left several large pieces because they were simply too heavy to carry. We piled them by a tree trunk on the west side of the road. We also hiked on a little farther to the scarp formed by the landslide. There are trails leading onto the scarp area. Although we didn’t find much, it was an interesting sight!
The breeze picked up as the sun set and we headed back to the car at Guffy Campground. It had a chill edge to it and reminded us that we were indeed at elevation. So we had some exercise and fresh air, found some actinolite, and stayed cool! This was certainly a great day trip!