U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
|Hollister Field Office|
Obsidian Artifacts Studies
The majority of artifacts sampled came from prehistoric archeological sites located in Fresno and San Benito Counties. Preliminary results indicate that the predominant (or "preferred") source location that Native American California Indians utilized for obsidian stone tools was in present-day Inyo County at the Coso Mountains. The second most 'popular' source for obsidian to make artifacts also came from a trans-Sierran source called Casa Diablo located in present-day Mono County. The remaining 20-30% of the obsidian source material comes from the northern California coastal mountains in present day Lake and Napa Counties.
Obsidian studies in west-central California are important in understanding prehistoric archeological sites because there are no local sources of obsidian for people to quarry; this meant that people had to trade or travel over long distances (over 100 miles) to obtain this material. One reason obsidian was favored as a lithic (stone) material for making sharp tools like projectile points (arrowheads) is because of the glass-like qualities of obsidian rock.