For once those black crystals are not natural. This bottle is entirely made of borosilicate glass, including these "crystals", which have no other use than to bring a black touch to the center of this transparency.
Food safe, if you wanted to poor a drinkable liquid in it...
Color/Finish: GLASS
Material: GLASS
Width: 11 cm
Height: 23 cm
Depth: 11 cm
Unique Piece: No
