This is a type of glass invented by Ercole Barovier in 1940 consisting of an
application of colourless glass grit onto the surface of an object
during its production.

When the object is then heated, the particles are
partially melted and adhere perfectly.
To enhance the material,
some pieces of gold leaf are on occasion encased between the surface and
the grit, with the object being subsequently iridized. 
This technique was used for a series of bowls and vases with a marine
inspiration and even in field of lighting, due to the pleasant light
diffraction effects on the uneven surface.