Venetian mirrors: Murano glass, styles and care

A Venetian mirror is a sheet of glass made on the island of Murano, near Venice, then cut, bevelled, engraved and silvered by hand, and finally framed in glass rather than wood. Its golden age ran through the sixteenth century, when the Venetian Republic kept the craft inside the lagoon and the mirror became one of the most expensive objects a household could own. Understanding the material, the workshop sequence and the main styles makes it easier to judge, place and keep a mirror at home.

What makes Murano glass different from ordinary mirror glass

Murano glass is a soda-lime glass, made from silica, soda and lime, and it is the raw material behind almost every mirror described as Venetian. The island's furnaces worked with a glass that could be blown thin, coloured in the mass and worked while hot, which allowed shapes that flat glass production elsewhere could not match. A mirror begins as a blown cylinder or a flat sheet, depending on the period and the workshop, and the glass is then cooled slowly so that it does not crack during the later stages.

The distinction that matters to a buyer is between the glass and the silvering. The glass carries the shape, the colour and the decoration. The silvering is the reflective layer applied to the back, historically a tin and mercury amalgam, later replaced by silver nitrate and then by industrial processes. A mirror can have old glass and a modern reflective layer, or the reverse, and the two are assessed separately. For a fuller account of the material, the furnaces and the techniques that grew around them, see this explanation of Venetian mirrors and Murano glass, which sets out the history and the workshop vocabulary in plain terms.

The workshop steps, from cutting to silvering

A mirror passes through a fixed sequence of operations, and each one leaves marks that can be read later.

Cutting. The glass is scored and broken to the required outline, or shaped with a diamond wheel. Straight edges are easier to keep true; curves and shaped crests demand more time and produce more waste.

Bevelling and faceting. A bevelled edge is a flat angled band ground along the border. Faceting goes further: a series of small flat cuts, often in a repeating pattern, ground into the edge or the frame. Facets catch light at different angles and give the mirror its characteristic sparkle. The work is done on rotating wheels with progressively finer abrasives, and the glass is kept wet to control heat.

Engraving. Decoration is cut into the surface with a wheel or, in some traditions, with acid. Motifs are usually floral or foliate, and they are shallow: the aim is to interrupt the reflection, not to pierce the glass.

Silvering. The back of the glass is cleaned, then coated with the reflective layer. Traditional silvering used tin and mercury, a slow and hazardous process. Modern silvering uses a sprayed silver solution activated by a reducing agent, followed by a protective copper layer and a coat of paint. The quality of the seal at the edges determines how long the mirror stays bright.

Finishing. The frame, the crest and the small glass rosettes or borders are assembled and fixed, often with metal pins and a backing board. The final step is cleaning and inspection against a dark background, where any cloudiness or lifting of the silvering becomes visible.

What are the main styles and shapes of Venetian mirror?

The styles are easier to recognise than to date, because workshops have continued to make older forms.

• Crown mirrors. A rectangular or arched central plate with a shaped crest above it, often pierced and decorated with engraved flowers. The crest is the most fragile part and the first place to look for repairs.
• Crested mirrors. Similar in outline but with a lower, wider crest and a more restrained border, usually a simple bevelled frame.
• Oval mirrors. An oval plate inside a faceted glass frame, sometimes with a small crest. Ovals suit narrow walls and hallways.
• Bubble mirrors. The frame is made from small convex glass pieces, set in a regular grid. The bubbles distort the room around the mirror and are usually modern in date.
• Mirrored furniture. Small cabinets, consoles and tables faced in mirror glass, often with engraved panels.

Sizes run from small dressing mirrors of around 40 by 60 centimetres to overmantel mirrors of two metres or more. Large pieces are usually made in sections, with the central plate separate from the frame, which affects both weight and how the mirror is hung.

How do you hang and place a Venetian mirror at home?

A Venetian mirror is heavy for its size, and the frame is glass, so the fixing matters more than the position.

Use two hooks or a French cleat rated well above the weight of the piece, fixed into masonry or into a stud, not into plasterboard alone. The bottom of the frame should sit slightly away from the wall so that the glass does not touch it. Avoid positions above a working fireplace, where heat and soot will attack the silvering, and avoid direct sun, which fades the backing over years.

Placement is mostly about light. A mirror facing a window reflects the brightest part of the room and shows the glass decoration clearly. A mirror on a side wall catches glancing light, which is where facets and engraving read best. In a hallway or above a console, a crest mirror works as a vertical element; in a bathroom, keep the mirror away from the shower, since constant moisture is the main cause of edge failure.

How do you care for an old mirror?

Dust with a soft brush or a dry microfibre cloth. For the glass itself, use a small amount of distilled water on a cloth, or a cleaner without ammonia, and never spray directly onto the surface, because liquid runs down and reaches the silvered edge. Dry immediately.

Do not use abrasive pads, and do not attempt to polish the reflective layer: the silvering sits behind the glass and cannot be reached without dismantling the mirror. Cloudiness, dark spots and lifting at the edges are signs of moisture in the backing, and they are treated by a conservator, not by cleaning.

For storage or moving, wrap the mirror in acid-free tissue, then in bubble wrap, and keep it upright rather than flat. Glass frames crack under their own weight if a large mirror is laid down. Label the wrapping so that the crest is not used as a handle.

What to check before buying

Look at the mirror in daylight and from an angle, not straight on. Check the edges of the silvering for dark lines, check the crest for replaced pieces, and check that the frame is glass and not painted wood imitating glass. Ask whether the mirror has been re-silvered, and if so, when. A re-silvered mirror reflects well but is no longer original; an original mirror with slight foxing may be more interesting and is certainly more fragile.

Finally, measure the wall before you commit. A Venetian mirror is a fixed object with a strong outline, and the space around it is part of how it reads.