Basalt or worn obsidian?

[Out Of Time]

I'm almost certain this old point is obsidian.

It's so worn that all hint of flaking is gone.

Also developing a new rind from exposure.

But maybe, just maybe, it's actually basalt.

There are little hints of the shine that charactarize obsidian (also the most common lithic in area) but it has a granular quality that looks like basalt I've seen in photos.

If it is basalt, it might be very old indeed and an exciting first find for me.

Curious if a more experience eye can make the call.

 

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[DizzyDigger]

I'd go with basalt.

 

[joshuaream]

I’d put a bright light (cellphone flashlight works) on the edge and see what you get for translucency. Basalt in your area isn’t very translucent, and even the opaque obsidian should show some light coming through.

 

[Al D]

Looks like basalt to me

 

[Out Of Time]

I’d put a bright light (cellphone flashlight works) on the edge and see what you get for translucency. Basalt in your area isn’t very translucent, and even the opaque obsidian should show some light coming through.

So I tried this test.

No translucency apparent.

But...I also tested a bunch of other known obsidian pieces and found that much of the older stuff is the same.

This local Napa stuff is very black and dense and only shows light when sliced very thin.

I did have few samples of old worn obsidian that showed translucence but they were all Clear Lake source, which is a greyer and more granular glass.

I think the only sure test would be to scratch it.

If it's shiney it's obsidian, right?

 

[ToddsPoint]

It looks to me like you have dacite. Gary

 

[Out Of Time]

It looks to me like you have dacite. Gary

View attachment 1748002

Interesting idea.

Perhaps it's possible.

I've never heard of dacite artifacts found in this area (Napa, Ca).

Finding anything other than obsidian is rare as quality sources are close by.

Once in a while I've found quartz and chert but hadn't heard of dacite till you mentioned it.













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