Glacial Pass Concretions
AKA: Glacier Pass Siliceous Mudstone
Description of Physical Characteristics:
Color:
Glacial Pass Concretions has a dark gray cortex with a dark gray
outer layer and a light brown chalky center. Artifacts tend to
utilize the outer layer with colors ranging from dark gray or brown
brown to beige, and greyish brown with some purplish brown. Silica
veins may be present.
Texture:
Medium to fine grain
Luster: Waxy
Translucency: Opaque
Silica Fabrics / Fossils: Present
Patina: Milky grayish brown
Heat Treatment:
Heat treatment does not change the flaking quality, but increases the
luster from waxy to vitreous and produced reddish or purple hues.
Knapping:
Distribution:
Glacial Pass Concretions is thought to be associated with the Fernie
Formation of Alberta. It occurs in nodule eroded from the shale in
the eastern edge of the Rocky Mountains in Alberta.
Projectile point made from this material:
Heat treated
Pictures Provided By:
References: (See Reference Page, Entry Number):
Similar Material:
Commonly made projectile point from this material:
Archaeological Context:
