Any idea if this is shell or something else?

Do all the beads have that 'grain' you show in the close up? If so, not shell. Blue one definitely not. White not if look the same.

 

White ones look like glass?

 

The backs of them appear to be smother and the front have that but all different.

 

Maybe ostrich egg shell beads?
Ostrich egg shell beads are made in Africa (obviously).

 

If I understand correctly, any appearance of striations, etc., is only on 1 side of each bead, blue & white?

 

Just the white ones.

 

At first, I agree. It's the 'chipped' edges and uniform thickness when you see them all lined up that immediately jump out at me to make me think "ostrich" ... you see them a lot in the 'Native American' necklaces (meaning, fake)

But then, I disagree. The layer lines are typical of seashells, not eggs generally.
https://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj40YqS3MPiAhUFVN8KHRgWAkQQjhx6BAgBEAM&url=https://www.sciencedirect.com/science/article/pii/S0305440317301115&psig=AOvVaw2OmNiwuzzwEBlpjZSkce3T&ust=1559321658128482

The egg shells are uniformly 'granular', bc the bird deposits the shell in biochemical bits, and not in layers. Not sure if the rings can be formed in times of stress or not, but it would be very uncommon. IMHO.

 

maybe bone. Nah. too irregular on the grooved side.
https://www.thebeadchest.com/collections/bone-beads/heishi-shape

typical ostrich beads

 

I had never heard of ostrich egg shell beads before, although have seen carved ostrich eggs.

The blue beads have texture around the sides too:



The one cross section shown looks very much like ivory; are we seeing Schreger crosshatching on the edges?

 

I always thought there was something funny about birds. Now I know why.

 

The blue beads could be ceramic of some sort?

 

The use of monofilament & a barrel clasp that looks like inexpensive ones found now says to me the stringing was relatively recent. Beads could be any time before. India will dye ivory henna red; don't know if they would do blue?

 

It is one of those surfer necklaces, maybe a surf or beach shop will have more info.

 

Now there's an example of cross-hatching.

 

They are all different on the inside. Looks like dyed something or other.

 

Ceramic, glazed?
Try surfer sites.

 

On the right side of the right hand bead you can also see the lines that show in the other direction. Said to be pre-ban ivory.

 

I'm stuck on "seashell"... those chipped edges are b/c calcium in seashells is much more of a brittle structure than in bone. Bone is a "hydoxyapatite" [god, I haven't used that word since college]. And it seems that, besides the really 'groovy' bead, and I don't mean that as a surfer dude, they seem to have a slight depression or concave surface to them, more shell like. Maybe both? Got mixed together when the surf shop dropped them?