ID stone bead help please

I think this necklace has been made up from random beads.
The transparent beads have uranium glass centres and the green test as glass. The brown translucent ones look slightly like agate but are evading ID at the moment so any ideas are welcome.
They test as a stone and my presidium tester says Nephrite - is agate a similar hardness?
What is the crackle effect ? Heat treated?
The clasp is silver and Chinese and it’s strung on modern wire. Thanks for any suggestions.

 

Agate is a form of quartz, but depending on type/composition/cut/polish can test quite low on a presidium meter, so they could be given the reading. As they are relatively transparent they are on the boundary of agate/carnelian. The crackle is unusual, looks as if they had been deliberately quench crackled.

Edit: Many polished stones don't give a reading on a presidium meter, so they are not necessarily glass, although in this case I think you are right (on the green ones).

 

Yes, the crackle is different on every bead.
Could be carnelian, I didn’t think of that.
Thankyou.

 

All of the beads look like glass to me.

 

Green are glass. Brown test as stone.

 

I don't trust testers. The distance between glass & stone is not far. I see a lot of carnelian & sard; these do not look like it to my eye.

 

The Chinese do love carnelian though.

I bought a silver sixpence bracelet yesterday with one of those Chinese export clasps, so the components obviously got shipped here.

 

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