Correction:

The article “Unusual Hoard Set in a New Home,” Aug. 12, inaccurately described the rarity of San Onofre Breccia. It is glaucophane which gives boulders a bluish hue that only occurs in three places in the world. Also, the source of geologist Fred Pratley’s comment was inaccurately described; it was from the South Laguna General Plan, written by Fred Lang and others.