Synthetic opals are very common in the lampworking industry. This is because real gemstones, minerals and other foreign objects put an immense amount of stress in the glass. This results in a very unstable product or the glass cracking shortly after it is encased. The wine stopper itself is made of 304 Food Grade Stainless Steel, that is secured to the glass with an epoxy rated for 3,300 PSI.
Opal Wine Stopper