I had planned my next SiO2 post to feature colorful amethyst but it proved surprisingly hard to photograph, like most of the rocks and minerals in my small new collection. So instead you get your silicon dioxide here in the form of this native American Indian projectile point/knife (ppk), often popularly called an arrowhead.

 

The chemical sedimentary rock chert, formed as nodules or lumps mostly in limestone, was the strategic material of the paleolithic, prized by early humans and other hominids for its sharp-edged conchoidal fracture producing excellent cutting and chopping tools. And chert retains sharpness because it’s very hard at 7 on the Mohs Scale.

 

Unknown provenance, age or tribe of this arrow, knife or spear point, my Dad gave it to me saying they easily found them an just picked them off the ground in the old days in South Alabama.

Concave side above: large at 2.25 in x 1.75 in x .4 in (57 mm x 45 mm x 10 mm) if shot from a bow it surely would have turned toward this dished side, perhaps it was attached to a thrusting spear shaft.

Color: Chert occurs in a wide variety of colors. Continuous color gradients exist between white and black or between cream and brown. Green, yellow, and red cherts are also common. The darker colors can result from inclusions of sediment or organic matter. The name “flint” is often used in reference to the darker colors of chert. Red to reddish brown cherts receive their color from included iron oxide. The name “jasper” is frequently used for these reddish cherts. Geology.com

There has not been much call for chert in the last 10,500 years but demand could increase if we keep upping carbon levels in the air. Nowadays it’s used only to keep flintlock pistols shooting.

I use Shotwell Image Viewer to manipulate photographs and I highly recommend it, don’t know of a MS Windows equivalent. However I am finding taking accurate pictures of rocks and minerals to be a bigger challenge than I anticipated and I feel the need to explain discrepancies, a sure sign I need to learn to take better pictures of these objects.

 

 

 

Unless noted,text/images by todgermanica, noncommercial use free with attribution. Ad clicks pay only WordPress-not me.