Wrightwood Actinolite
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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!