Faceted "block" vases and bowls similar to the ones shown below have been popular since the 1950's, and production has continued right up to today. There have been many factories in the Murano region which have made glassware in this style, and as such it is difficult to be certain of the manufacturer without labels or signatures present. Companies that have produced glassware in this faceted style include Mandruzzato, Campanella, V. Nason, Formia, Bucella Cristalli (retailer, & grinder / polisher of supplied "rough" pieces), Pagnin & Bon, Tiozzo & Ferro, Vetri Molati, Cesare Toso, Gianni Seguso and Oball. The vast majority of these faceted Murano glass items contain two or more suspended coloured layers of glass in a third layer of clear glass, using the very popular sommerso technique.
Important note: As with most sommerso glassware, it is very common to find these wrongly attributed to Flavio Poli, a designer who became famous for his sommerso designs. However, Flavio Poli worked for the Seguso Vetri d'Arte factory, whose designs are very well documented, and there are no records at all of them ever producing these faceted sommerso items. Sadly this does not stop inexperienced sellers from copying the incorrect Flavio Poli attribution, if their research only consists of a quick Google or eBay search.