I have an OLD 10 strand turquoise heishi necklace. It’s falling apart because the string is so old and there is no clasp its all tied in one big knot.
The beads are delicate and some are crumbling.
The very old necklaces were strung with string, often heavy cotton thread such as coatmakers used to use to sew on buttons. Eventually with time, the thread deteriorates from wear and moisture. We have had some extremely heavy old turquoise necklaces in our pawn shop and I was so surprised to see that they were strung with string, and yet that was the way.
Today the artists can use all kinds of synthetic (and long lasting) threads and cords, memory wire (stainless steel wire that retains its shape), imitation sinew, elastic cord and foxtail which is a strong woven nickel chain that resists abrasion from beads sliding and moving.
As far as the turquoise stones, the very old stones were completely natural, that is, not treated or protected in any way. That’s why they are starting to crumble because turquoise, over time, can become dry and brittle and it reacts to oils and other things in the environment that cause the stone to break down.
Today almost all turquoise heishi is made from natural turquoise that has been treated in some way to protect the color from fading or changing and to keep the stone from crumbling. You can read about the various types of Turquoise here
The old style way of fastening a multi-strand necklace together is a squaw wrap which doesn’t involve any fasteners. Here is an example of what a squaw wrap looks like on a single strand fetish necklace.
Now as far as your 10-strand necklace, I wish I could recommend a Native American artist to restring your treasure, but I simply do not have someone to refer you to. When I have researched beads for other Non-Native American projects, and searched something like “stringing beads” in google, I came upon quite a number of (non NA) people that make new heishi necklaces and think you might find someone that way to restring your necklace.
As far as restoring your stones, I think leaving them as is would be best as that way they show the wabi-sabi of their vintage character.
I truly wish I could be more help, but perhaps by posting this, someone will reply that is a Native American jewelry restorer and I can put you in touch with each other.
Best of luck, Paula