Sorry...forgot to add the height...it's 23.5 cm tall. It isn't smooth and is made in exactly the same way as yours .
As you say it is very much like a mosaic with the marvered in flecks with this bubbly , white 'cement' over the black glass base. This bubbly 'cement' <----- don't know what else to call it !, looks to be a creamy white colour under the base where you can see the original non-drawn-out shape of the aventurine flecks. There does seem to be a colour reaction going on with the cement which has a light green tinge in places. Also, on mine, it seems to have mixed/reacted with the black glass base as the cement in darkish grey in places.
It's an interesting technique and I would like to know how it is done. I don't understand why the aventurine flecks weren't directly marvered into the black glass.....why use this bubbly 'cement' stuff ? Cheers, Mike.