Antique crackle glass decorative hanging ball ( Xmas decoration ) we believe this is very early probably 1920s with the art nouveu copper hook heavy well made item some age related wear 11 cm tall 8 cm wide 
 although probably there when item was made 
The history of crackle glass can be traced back to the 16th century, when glass artists in Venice developed a unique technique to create the effect:
Blow molten glass into a small bulb
Submerge the bulb in cold water, causing the glass to shatter due to the extreme temperature change
Reheat the glass, shape it, and seal it to preserve the crackled look 
 
The technique requires skill and practice to avoid shattering the glass completely or melting the cracks during reheating.