ArrowPoint

Named stone

Hozomeen chert

Also called Hozomeen chert quarry complex, Ross Lake chert, Upper Skagit chert

A kind of chert (and flint)

Hozomeen chertChert (and flint)West Coast & Plateau

Description

Hozomeen chert is the signature toolstone of the North Cascades, quarried in the upper Skagit River valley around Ross Lake on the Washington-British Columbia border. It formed on a deep ocean floor from the silica of radiolarian skeletons and now sits in ribbon-chert and massive beds among greenstone of the Hozomeen Terrane. The usual form is mottled black, dark gray, light gray or bluish gray, laced with a fine net of thin white veins, with a dull to semi-glossy luster. Rarer varieties include an even medium gray, a red jasper, a pale translucent chalcedony and a white stone with dark veins. Seventy radiocarbon dates show use from the early Holocene to historic times, and artifacts reached Puget Sound, Whidbey Island and Lake Chelan, an area of more than 25,000 square kilometres.

How to identify it

Colour
Most often strongly mottled black, dark gray, light gray or bluish gray, sometimes with ochre tones; rarer varieties are even medium gray, opaque red ('jasper'), translucent light gray, green or blue ('chalcedony'), and opaque white with dark veins (Mierendorf and Baldwin).
Texture
Microgranular quartz (90 to 95 percent, crystals 2 to 10 microns); fracture ranges from smooth glassy conchoidal to hackly and irregular.
Luster
Dull to semi-glossy.
Inclusions
A reticulate network of thin white (sometimes black) quartz veins making up 1 to 15 percent of the rock; recrystallized radiolarian 'ghosts' visible under magnification.

Geology

Deep-ocean radiolarian chert of the Hozomeen Terrane, interbedded with greenstone and other metamorphic rocks. Outcrops in a core area of about 64 square kilometres near Ross Lake appear as ribbon chert and massive jointed beds from alpine ridges down to montane slopes. Glaciers of the Cordilleran ice sheet plucked chert from bedrock and spread cobbles and boulders as float across moraines, terraces and fans, which were also used as secondary sources.

Where it comes from

West Coast & Plateau

States

Quarries and outcrops

  • Hozomeen chert quarry complex, Ross Lake area, upper Skagit River valley, Whatcom County, Washington (North Cascades National Park Service Complex)
  • Lightning Creek area, Ross Lake (95 percent of flaked stone at 44 sites)
  • Glacial float on moraines, terraces and alluvial fans of the upper Skagit valley

Used by

  • Early Holocene onward: 70 radiocarbon dates cluster at about 6100-8000, 3600-5400, 1000-2800 and 150-600 radiocarbon years BP (Mierendorf and Baldwin)
  • Coast and Interior Salish territories: artifacts found from the Fraser River to southern Lake Chelan and south to Lake Sammamish, including possible Western-stemmed lanceolate forms on Whidbey Island
  • Nlaka'pamux (Lower Thompson) elders told James Teit of trips to the Skagit headwaters for arrowhead stone (type of stone not stated)

Look-alikes

Stones that are easy to confuse with Hozomeen chert.

  • Other gray Northwest cherts described in old reports only as 'gray chert' or 'gray chalcedony'; Mierendorf and Baldwin re-identify some of these as Hozomeen chert from photographs, so field labels are unreliable

Sources

  1. Mierendorf, Robert R., and Kevin E. Baldwin. 2015. Toolstone Geography in the Northern Cascades of Washington and Adjacent Areas. In Toolstone Geography of the Pacific Northwest, edited by Terry L. Ozbun and Ron L. Adams, pp. 76-106. Archaeology Press, Simon Fraser University.archpress.lib.sfu.ca (opens in a new tab)

All materials