Bs Jewellery Store
https://www.ebay.co.uk/str/bennettsjewellerystore 
UK Seller

Clear Opalite Moonstone Gemstone Pendants
on
925 Silver 20in Necklaces

Gemstone Pendant Sizes: Mixed

Necklace
Necklace = Round Link Trace chain
Colour: 925 Silver
Length: 51cm 20ins
Link Size: about 1mm
With Lobster Clasp

Natural Opalite (as opposed to the man-made Opalite) shares the same basic chemical properties as Opal. 
It is made of tiny spheres of Silicon Dioxide which stack onto each other in a pyramid grid shape. 
This grid is what allows the cat’s eye effect to be displayed when the stone is cut into a high domed cabochon.
Natural Opalite is referred to as "common opal" to prevent confusing it with glass Opalite.

Thanks for looking