Napa Glass Mountain Obsidian
(Napa Valley Obsidian)
Description of Physical Characteristics:
Color: Napa
Glass Mountain Obsidian ranges from a
black to a pale charcoal gray or a coffee
brown with streaking of coffee brown or reddish brown occurring.
Texture: Fine grain
Luster: Glossy to vitreous
Translucency: Opaque, translucent on very thin
edges.
Silica Fabrics / Fossils:
Patina:
Heat Treatment: N/A
Knapping: High knapping quality
Distribution:
Distribution Comments:
Napa Glass Mountain Obsidian is associated with the upper member of the
Sonoma Volcanics and occurs as nodules in a matrix of tuff and perlite
on Glass Mountain in the northern Napa Valley near the town of St.
Helena, Sonoma County, California.
Projectile point made from this material:
Pictures Provided By:
References: (See Reference Page, Entry Number):
Similar Material:
Commonly made projectile point from this material:
Archaeological Context:
Numerous prehistoric quarries are located on
Glass Mountain and have been found in many archeological sites in
California.
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