Heat treated birdie?

[Stasdab]

Hello, I found this bird point a few weeks back eroding out of a high creek bank in will county Illinois . It is a 1 3/8 long shows percussion flaking with some pressure flaking retouch. The lower left corner shows what i believe is heat treatement. I pick up all flakes i come across, the area is generally lithic poor and everything is used to its fullest. I've found matching flakes that look very similar near the area i found the point. My ? Is can you type the point or assign a timeperiod and can you guys confirm if its heat treated . Ive inserted a pick of the flakes found near, the heat treated flakes i believe are in the upper right .

Thanks

[JoshinMO]

Good find! Could be or it could be minerals etc from the water?  :laugh: Looks from the time period heat treating was used often though.

[Stasdab]

Thanks Josh, what type of point you thinking. I thought maybe a matanzas or some early woodland piece. Here is a better pick of the flakes i found that i think is heat treated. The one in the lower left corner i thought was a point till i looked at it.

[painshill]

On another forum, someone was asking how to identify whether material has been heat-treated and this was my reply:
Heat treatment improves the knappability of cryptocrystalline siliceous materials such as cherts by altering their structural integrity. For an isolated piece you could never be completely sure without resorting to analytical techniques such as thermoluminescence testing. Intentional alteration doesn’t give a defined end point, so you really need to be familiar with the properties and appearance of the material before it has undergone alteration, so that you have a comparative point against which to judge the improvement. That’s easy to judge in some areas of the US where the quality of lithics is poor to begin with (providing you’re sure you’re not looking at something that’s been traded from elsewhere). Also easy in specific quarrying areas where you find material which exhibits higher quality than the quarrying site could yield. Rather less easy in areas where the lithic quality is high to begin with. Not every material benefits from or needed to be heat-treated.
Controlled heating of cherts to temperatures above about 300 degrees Celcius causes melting of microscopic impurities in the intercrystalline spaces. The melted impurities act as a flux, fusing together the individual cryptocrystals that form the body of the chert to create a more homogeneous material which has greater elasticity and consequently a greater likelihood of fracturing conchoidally. That is, it becomes more glass-like in both appearance and tensile properties.
The general change in appearance in terms of texture and lustre is usually most apparent on surfaces which have actually been subsequently flaked. The gloss increases markedly and the surface feels smoother and “waxier” to the touch. There is often a colour change too which varies enormously according to the material, but pinks and reds appearing as diffuse bands and swirls are particularly common.
The adverse effects of internal flaws on knappability are also greatly reduced and that’s apparent where such flaws can be seen in knapped areas. In general, heat-treated material transmits the forces exerted by a knapper much more evenly and the adverse influences of fossiliferous inclusions, microfractures etc is largely negated. Flaking scars travel cleanly through the chert without deviating unevenly around flawed areas.
Also, in general, material which has been heat-treated will have been knapped by soft-hammer percussion and/or pressure-flaking rather than hard-hammer percussion. Flakes tend to be larger (and particularly longer), normally feathering out rather than step-terminating and result in tools with much thinner and sharper edges.
It’s also sometimes possible to judge whether heat treatment has been applied from accidental over-heating in some areas. Although intentional heat-treatment requires a high degree of control, sometimes there will be areas of material which have been over-heated. Most usually, that results in surface “crazing”, localised structural disintegration to whitish powdery areas, pot-lid fractures and a reticulated appearance on knapped surfaces. All of those features are however also likely to be present on unintentionally heated material (from wildfires etc) and – in the case of pot-lid fractures – from frost damage.

[Stasdab]

Well it could be heat treated or just mineral staing, does anyone have idea on type. I'm thinking matanzas, raddatz