At least 2 possibilities:
An exciting project-
If you want to add smaller beads with similar holes that will complement your feature at the centre then try the maximum number of doubled threads that you can pull through- otherwise a short bit of tigertail or even soft wire through the long bead and make a very small loop at each end. Then you can attach thread on either side to the loops and fill both sides with good matching small beads - or add many strands of thread in toning colours - thicker than what fits through the long narrow hole, and do interesting substantial braiding or macrame up to the clasp - or a knot of both left and right strands together if long enough to go over the head.
And show us what you do!

Thank you Stefany! I love your enthousiasm!! I am a very slow'beader', it might take some time before this is finished.
I like your first idea with the loops but I won't use smaller beads for the rest of the necklace, because I just don't have pyu or other ancient beads that go with it. I am not sure I have some small ancient beads that will cover the loop, we'll see.
When you talk about thread what do you use? I like natural material but I always struggle with thickness, strength, durability. I often have to rule out silk, leather, cotton when using those small beads... so my conclusion is thin synthetic mala thread, but never used it so far. All suggestions are welcome!!

i have all colours on reels of what may still be called bonded nylon- a spun multifilament nylon yarn originally intended for sewing machines for leather goods, shoes etc. it doesn't stretch, is extremely strong, comes in colours and the fibres are smooth and continuous - sort of lubricated or polished smooth (=bonded) so as not to snag going through a machine . i never have the best thickness but one can experiment mixing strands /colours which usually makes even the knots look interesting.
"beadsmith" discovered it long after i had been using it and they have a version of it in some colours on small cards.
i have been teaching threading and knotting using it for many years.
another hint- if you make your own needle with a length of fine fuse wire, twisted together at the point end then you save on needles, it allows you to create a bulky line of a mix of skinny threads all doubled- and for delicate beads its better to be able to fill up the hole space so your precious bead is cushioned, it can't move from side to side and risk breakage of the bead or the thread fibre.
if you want to reprooduce an ancient necklace and use silk or other authentic natural thread that's fine but it will have a limited life- if it is to be worn a lot then it justifies the strongest as well as most attractive thread, so go for something "synthetic" that does the best job...
i'm not such a fan of nylon coated cable unless its the only thing that'll fit, because its too easy to use for any beads and can let beads grind together, or cut just like cheese wire...

enough now- its my bedtime- tomorrow i'm taking a week off as a holiday from my lockdown in London to spend with the grandkids etc...

Stefany is a master in stringing techniques, so that is some vert good advice.
Another option would be to use a metal pin that would go through the entire bead, make loops at either end, and then use any type of cord attached to that that you want. Could even add it to a metal chain.
It would allow for the bead to sit horizontally without the risk of too much strain on the ends.
Or make it into a pendant, again with a metal pin. A ball on one end, or a small loop with a dangle, put through the bead, create a loop on the other end, and then you can wear it vertically.

I don't have a clear idea what you aspire to make as a necklace.

I think the advice from Stefany and Floor are good ideas.

You might want to consider the Softflex line that is 24 K gold (if you are not planning to cover the line with beads).

It is very strong and quite pretty! I have even knotted it to hold a pendant that went onto a gold neck-ring.

You can find it here: https://www.amazon.com/Soft-Flex-Extreme-Beading-Wire/dp/B005S4BZMU

Have fun! Jamey

A great bead, Martine! If you are thinking about making it into a pendant - here are some things I've used on single beads. Bead caps or old African brass beads look good with old beads. Often a smaller bead on the bottom seems to add a nice touch. Here are two examples - much smaller beads than yours though! I use gold-filled, sterling silver, or brass wire, depending on the effect I want. To finish the bottom of the wire, make a tight flat coil that is big enough to be the "stopper" at the end.
Another idea is to add a silk tassel to the bottom end.

Please show us the finished necklace!

I originally thought of mounting it as a pendant but I am afraid I might bump into things when wearing and damage it.
I just want to make a simple necklace and let this bead speak for itself. Thank you for all the useful suggestions, now I’ll have some fun trying out the different possibilities.

So many Forum peers joining voices as a well tuned chorus of angels --do listen to Arvo Pärt's Kanon Pokajanen! Alas, they have exhausted all available nonsensical options.

Shame, because I was tempted to jump into the pool!

Still, let me try...one last risky choice is offered hereafter:
Using the appropriate tool, cut this long bead into six shorter ones, which you can strung on any convenient thread, with a few "attendant" disc beads in between (gold, shell, whatever)to enjoy a really nice, wearable choker.

Oh,I forgot that you want to use this bead "AS A SINGLE BEAD".
Discard my advise...

Nishedha jumped into the pool!

Thank you Nishedha, this was the best so far. Chamber choir Aquarius with Arvo Pärt Kanonon Pokajanen on the background agrees. The only thing missing is the pool!
What beauties have you been creating during this confinement. I could use some single bead inspiration.

Thank you for being so forgiving.
As a way to counteract the enforced social distancing -- myself most of the time a confined bachelor -- I indulged in a kind of gentle frenzy, went berserk after drinking the sweet wine of solitude, relaxing open-eyed at night till it dawned upon my mind: nishedha, go beyond singles, allow the interplay of a couple.
And a couple I found, hidden shyly in the recessed corner of a forgotten box. Two shiny crystals, to be set in a ring.
And was healed.