How do I identify opalescent glass?

Opalescent glass displays a milky, translucent quality that shifts between blue and amber tones when light passes through it. The effect is particularly pronounced along raised moulded edges and high points of relief. Makers achieved this appearance by adding specific chemical agents to the molten batch before press-moulding the vessel into shape.

What is the difference between a coupe ouverte and an open bowl?

A coupe ouverte is a French term for an open bowl, typically featuring a wide, shallow profile and heavy moulded decoration. These vessels were designed primarily for visual impact on a table or sideboard. Standard open bowls may follow simpler geometric or blown forms without the specific French press-moulded sculptural reliefs.

How were overlay glass bowls made?

Overlay glass involves gathering a core of clear or contrasting crystal and dipping it into a layer of coloured molten glass. Once cooled and shaped, sections of the outer colour are cut away to expose the material beneath. This subtractive process creates bold, two-tone visual effects popular in Belgian production of the period.

Where were Monart glass bowls produced?

Monart glass bowls were produced in Scotland by the Moncrieff family, drawing on techniques influenced by Spanish glassmaking traditions. They are recognised for their free-blown forms and suspended coloured swirls. These pieces rely on skill in the hot shop rather than mechanical press-moulding.