Provenance--the family collection was gathered on sites along the Wabash River--was this the Indiana side of the stream or the Illinois side, no tags, and a tan chert that isn't definitive. I've seen similar chert found here in S.W. Indiana, 'cherty' forms of our Holland Flint. Unless you can find the actual deposit of flint/ chert, you're working on "I've seen this stuff before" type experience. Patina, that's "no brainer", absolutely every fine flake on the Kirk Stemmed is authentic. The base is somewhat bifurcated, well ground, and slightly fluted. Why Kirk Culture would grind the bases on their stemmed points and not their Cornernotched points, that's for some doctoral student to write a paper on--I just know that was their pattern. Length is slightly over 2&1/2" by 1&1/4", thinness is a fine 1/4" max in the basal tang area--toward the tip the blade becomes super thin--and the flaking becomes even better. There are white lines of silicate material running through the chert--close up photo should show them. Unless it only shows up under a 10x loop there is nothing I'd describe as 'damage'. The point is guaranteed authentic for life, period. Shipping is $5.00, and checks, cash, or M.O.s are welcomed. Sorry, I don't use paypal--Roy A.