String of Small Turquoise Beads w/Heishi Spacers

The string is ~48" long; there are 136 ~1/4" Turquoise beads, for a total weight of ~70 grams.
Their shapes are irregular, but many are similar in that they are 'tooth' shaped; larger on one end than the other. I suspect from the irregularity that they are roughly as-found...naturally shaped...with perhaps having been tumbled for polishing. I know little about Turquoise, so cannot say if they are 'treated', nor whether they are NA or Chinese; although the heishi seem to indicate the former.
The old friend I bought them from knew only that he got them in the 70's...he thinks. I welcome all your comments an' suggestions.
Thanks for lookin'!

 

ya the heishi suggests they're from here.....but the rocks do look tumbled and dyed.

 

I have to wonder if it's not imported/Chinese turquoise, strung in North America. The shell heishi are straight NA, but the turquoise looks wrong, and the hook and eye looks funny too.

 

Very nice necklace. This particular seemingly random shape of the turquoise beads is classic Chinese. A lot of Chinese turquoise has been exported to the US and elsewhere, and I think the necklace could be US-made.
It looks strung on artificial sinew, which is often used by Native Americans. The figure-8 loop of the clasp is seen on a lot of SW NA jewellery.

 

Under a loupe it looks similar to Nylon in terms of discrete fibers...but not in the way it's laid into thread; there seems to be a twisted & woven pattern to it. I can only see the material at the knots either side of the clasp, but have not seen that 'cordage' before. Thanks, AJ!

eBay has several (shorter) strings listed or sold under Chinese Export Knuckle Carved Turquoise. Apparently they're the shape of knuckle bones...who knew? At least one of them is similarly Heishi-spaced. Judging from another search, I have scored a modest bargain in my cost...I remain very pleased with them...an' with what this posting has taught me. Thanks...

 

Learned the word "heishi" and saw a picture of a Mercury dime. It was worth opening this thread. Thank you for posting, @wlwhittier !

 

I had heard the word but had to look up its spelling!
The dime was a size comparator; I've hoarded US silver coins since the mid 60's when they were replaced with our 'funny money'. They are attractive, an' I'm loath to part with 'em, but will eventually to keep myself in beans an' TP...Thanks, Fig!