Novaculite
The name novaculite derives from the Latin “novacula” (meaning “razor”). It’s a dense and hard derivative of chert (microcrystalline or cryptocrystalline quartz) varying in colour from white through to grey/black (sometimes with a bluish tinge) plus some variants in orange, brown and pinkish reds as a result of trace mineral impurities. It’s usually translucent (although that may only be apparent on thin edges) with a dull to earthy lustre if porous, and a waxy or glassy lustre if non-porous. Some types have a high carbonate content (up to 30%) and may be completely opaque; other variants have an opaque appearance similar to unglazed porcelain.
Generally, it has a higher degree of diagenetic alteration than chert and is formed by low-grade metamorphism of chert beds.
Native American Use
Novaculite has a conchiodal fracture like chert, but is much more difficult to knap in its natural state. Several of the variants respond well to heat-treatment with consequent improvement in structure and knappability. The Arkansas novaculite in particular was heavily mined by Quapaw, Osage, Caddo, Tunica, Chickasaw and Natchez peoples and traded over a very wide area outside the state. As well as its use for points, its hardness and abrasive qualities also made it suitable for use as a sharpening stone.
European Settler Use
European settlers in the Ouachita region also mined the Arkansas novaculite to produce sharpening and honing stones for metal tools and weapons. Cut and lapped stones were traded over wide areas outside the state and, in later times, for international export.
Although demand dropped away in the 1900’s and artificial alternatives became widely available, the whetstone industry still survives today, supplying a range of grades. “Washita Stone” has the appearance of unglazed porcelain, high porosity and is employed for coarse sharpening. “Arkansas Stone” is extremely fine-grained, has almost no porosity and is employed for honing razor-sharp blades.
Novaculite Localities
In North America, it occurs mainly in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of Texas. It’s very resistant to erosion/weathering and layers of novaculite in the Ouchita Mountains stand out as prominent thick ridges in the surrounding clastic sedimentary layers or as massive cliff features. The major outcropping for novaculite in Arkansas is near Hot Springs in Garland County, where the layer is about 10 feet deep.
North Carolina “Novaculite”
The presence of “novaculite” was reported within the slate beds of the upper part of the Uwharrie Formation of Orange County, North Carolina in 1822 by Olmstead. He noted that the most valuable bed was found at McCauley's quarry, seven miles west of Chapel Hill, describing it: “olive green in color, has a horny look, and is transparent on thin edges.” Emmons also reported other deposits as: “bluish black passing into purple, grayish, white and green of several shades, and sometimes banded”.
It was quarried in ancient times on an extensive scale a few miles west of Chapel Hill and knaps conchoidally, as evidenced by the fact that pretty much all of the arrow heads and spear heads found in the vicinity of Chapel Hill are made of this material.
Although it’s truly cryptocrystalline, the greasy talcose structure of the material suggests that it’s not a novaculite. Microscopic examination has demonstrated that it’s composed of feldspar, quartz, kaolin, and epidote. It’s a recrystallized volcanic mudstone, technically classed as an “apo-rhyolite”.
The name novaculite derives from the Latin “novacula” (meaning “razor”). It’s a dense and hard derivative of chert (microcrystalline or cryptocrystalline quartz) varying in colour from white through to grey/black (sometimes with a bluish tinge) plus some variants in orange, brown and pinkish reds as a result of trace mineral impurities. It’s usually translucent (although that may only be apparent on thin edges) with a dull to earthy lustre if porous, and a waxy or glassy lustre if non-porous. Some types have a high carbonate content (up to 30%) and may be completely opaque; other variants have an opaque appearance similar to unglazed porcelain.
Generally, it has a higher degree of diagenetic alteration than chert and is formed by low-grade metamorphism of chert beds.
Native American Use
Novaculite has a conchiodal fracture like chert, but is much more difficult to knap in its natural state. Several of the variants respond well to heat-treatment with consequent improvement in structure and knappability. The Arkansas novaculite in particular was heavily mined by Quapaw, Osage, Caddo, Tunica, Chickasaw and Natchez peoples and traded over a very wide area outside the state. As well as its use for points, its hardness and abrasive qualities also made it suitable for use as a sharpening stone.
European Settler Use
European settlers in the Ouachita region also mined the Arkansas novaculite to produce sharpening and honing stones for metal tools and weapons. Cut and lapped stones were traded over wide areas outside the state and, in later times, for international export.
Although demand dropped away in the 1900’s and artificial alternatives became widely available, the whetstone industry still survives today, supplying a range of grades. “Washita Stone” has the appearance of unglazed porcelain, high porosity and is employed for coarse sharpening. “Arkansas Stone” is extremely fine-grained, has almost no porosity and is employed for honing razor-sharp blades.
Novaculite Localities
In North America, it occurs mainly in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of Texas. It’s very resistant to erosion/weathering and layers of novaculite in the Ouchita Mountains stand out as prominent thick ridges in the surrounding clastic sedimentary layers or as massive cliff features. The major outcropping for novaculite in Arkansas is near Hot Springs in Garland County, where the layer is about 10 feet deep.
North Carolina “Novaculite”
The presence of “novaculite” was reported within the slate beds of the upper part of the Uwharrie Formation of Orange County, North Carolina in 1822 by Olmstead. He noted that the most valuable bed was found at McCauley's quarry, seven miles west of Chapel Hill, describing it: “olive green in color, has a horny look, and is transparent on thin edges.” Emmons also reported other deposits as: “bluish black passing into purple, grayish, white and green of several shades, and sometimes banded”.
It was quarried in ancient times on an extensive scale a few miles west of Chapel Hill and knaps conchoidally, as evidenced by the fact that pretty much all of the arrow heads and spear heads found in the vicinity of Chapel Hill are made of this material.
Although it’s truly cryptocrystalline, the greasy talcose structure of the material suggests that it’s not a novaculite. Microscopic examination has demonstrated that it’s composed of feldspar, quartz, kaolin, and epidote. It’s a recrystallized volcanic mudstone, technically classed as an “apo-rhyolite”.
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