Murano glass techniques at a glance

At a glance

Match is from piece to piece. No weights, prices or lead times are given.

How to read this sheet

Each technique changes four things a specifier has to write down: how the piece looks lit, how much glass it holds, how closely a second piece will match the first, and what the workshop has to be told in order to quote the right thing. For the history of the island and how the glass is made, read our journal guide to Murano glass techniques. This sheet is the other half: what each technique means on the drawing and the schedule.

Three kinds of statement are mixed in the table, so we label them. What the museums say is paraphrased from two sources we read: the Glass Museum Murano's English leaflet 'What is glass?' (GMM below) and the V&A's 'An A to Z of glass'. Our reading is a conclusion we draw from those descriptions, marked as ours. Ask is something only the workshop can say, and no source we read says it. We found no published figure for cost, lead time or colour repeatability by technique, so none is given.

What each technique is, from the museums

This is the sourced table: what each technique is, in the museums' words reduced to plain English. Nothing in it is our reading, apart from where it says 'our journal'. Italian names are kept because they are the words on a workshop's drawings; see also the chandelier anatomy and glossary sheet for the vocabulary of the fitting. Zanfirico, which our journal describes as twisting several coloured threads into ribbon-like patterns in the cane, is treated with filigrana: neither museum source we read has an entry for it.

GMM is the Glass Museum Murano (Fondazione Musei Civici di Venezia) leaflet 'What is glass?', English edition, page numbers of the PDF. V&A is 'An A to Z of glass', page updated 17 April 2024. Aventurine is dated differently by the two museums and by our journal: ask the workshop to describe its own colour range.

Weight: why the wall matters

More glass is more weight, and the amount of glass depends on the thickness of the wall as much as on the size of the piece. The museum describes sommerso layers as perhaps of great thickness, so ask for the weight, not the diameter. The arithmetic is simple geometry. For a hollow sphere with the same outside size and the same glass, the amount of glass is the outer radius cubed minus the inner radius cubed, and the weight follows in the same ratio. For a sphere 300 mm across, a 6 mm wall holds about 2.0 times the glass of a 3 mm wall, a 12 mm wall about 3.8 times and a 20 mm wall about 5.9 times.

The wall thicknesses are examples: we found no published thickness for Murano lighting glass, and layered sommerso uses more than one glass, so the ratio is a guide to scale, not a weight. What to do with it: have the workshop declare the complete lamped weight on the shop drawing for the glass as made, and give it, with the position and drop, to the structural engineer (see specifying Murano glass lighting and chandelier sizing and hanging heights). A change of technique after approval can change the weight, and so the frame and the fixing.

Matching: what can and cannot be repeated

'No two pieces are identical' is on our live pages, and the specification has to say what that means. The drawing sorts the techniques into four bands, from easier to harder to repeat. It is our reading of the museum descriptions: a form made in a mould repeats; a form shaped by hand is similar; a pattern placed by hand is approved on a sample; an effect that is partly left to the furnace can only be approved as a range. The workshop confirms the band for each technique it will use, at lighting scale.

• Do not write 'identical' for anything but a mould-blown set, and even then say what is identical: the form, not the colour or the wall.
• Name the elements that must match and ask for them to be made in one run, from one melt where colour matters (see Murano glass colour).
• Approve a sample in the technique and thickness you intend to use. A swatch in another technique reads differently.
• Write the limits down for a pattern or an effect (see acceptance criteria for handmade glass), and settle the remedy before production.
• Plan the spares. A replacement element made years later may not match one made now. Ask whether the mould, if there is one, is kept, and for spares to be made in the same run.

Naming a technique on the schedule

The workshop quotes what the schedule says. A line such as 'Murano glass pendant, blue' leaves the technique, the number of bands, the thickness and the match to the workshop's choice. The table shows the same lines written so that the workshop quotes the right thing.

Choosing by the look you want. A crisp horizontal colour break points to incalmo. Deep colour that seems suspended inside the glass points to sommerso. Fine lines or a net inside a clear wall point to filigrana or reticello. A scattering of small motifs points to murrine. Glitter points to aventurine, a beaten sparkle to battuto, a frosted or crazed skin to ice glass or pulegoso, and a hidden lamp and soft glow to lattimo. For each, ask the workshop for a lit sample at the thickness it would make.

Programme and cost. Our own pages give different programmes for Murano glass lighting, and the techniques guide says only that the technique shapes the lead time and the cost. We found no published figure by technique, so this sheet gives none. Ask the Murano partner which techniques add a stage, a second worker, a longer cool-down or a risk of remaking, and write its programme for each element type into the order (see our lead times page and the programme section of the Murano specification sheet).

Element [E1, pendant globe]: [free-blown / mould-blown from mould ref] in [glass type] by [technique], as shown on shop drawing [ref] and approved sample [ref]. The technique named for each element is part of the order; a change of technique, mould or colour recipe after approval is a variation needing written approval.

[Incalmo]: [2] bands, colours by sample [ref], colour break at [ ] mm, plus or minus [ ] mm, from [datum]. [Sommerso]: layers from inside to outside [clear / colour 1 / colour 2], wall thickness [ ] to [ ] mm stated by the workshop; complete lamped weight declared as made on the shop drawing.

[Murrine / filigrana / reticello]: pattern [type], colours by sample [ref], share of surface [ ] per cent. Placement and count vary from piece to piece; pieces are accepted as similar to the sample within the limits on sample sheet [ref].

[Aventurine / leaf / pulegoso / ice]: effect as approved sample [ref], viewed unlit and lit at [ ] K. The workshop states in writing, before approval, the range it will accept (for example flake density or crazing pattern) and any effect it cannot repeat. No exact repeat is expected.

Elements that must match [list] to be mould-blown from mould [ref] in one run; mould retained by [workshop] for [ ] years for spares. Spares: [number] of each element type, made in the same run as the order.

Standards and sources

• Fondazione Musei Civici di Venezia, Glass Museum Murano: What is glass? (English leaflet): pp. 7 to 10 read 5 Nov 2026; undated leaflet, with translation faults.
• Victoria and Albert Museum: An A to Z of glass: updated 17 Apr 2024; aventurine, filigree, reticello read 5 Nov 2026.
• Make Bespoke Studio journal: Murano glass techniques: leaf, iridised, aventurine, pulegoso and ice descriptions.

Questions we are asked

What is the difference between sommerso and incalmo?

Sommerso is layering: the glass is plunged into crucibles of differently coloured glass while it is worked, leaving transparent layers of colour, perhaps of great thickness. Incalmo is joining: distinct parts are added together while the glass is still hot, which gives a crisp colour band where they meet. On a drawing, sommerso needs a layer order and a weight, and incalmo needs the position of the colour break.

Which Murano technique makes the heaviest glass?

The museum describes sommerso layers as perhaps of great thickness, and a thicker wall means more glass. For the same outside size, a 12 mm wall holds about three and three quarter times the glass of a 3 mm wall. We found no published wall thickness for Murano lighting glass, so ask the workshop for the declared weight as made.

Can two aventurine or murrine pieces match exactly?

Not exactly. The museum says success with aventurine is to a certain extent a matter of chance, and murrine and filigrana are placed by hand, so the pattern differs from piece to piece. Approve a sample, write the range you will accept and agree the remedy before production.

Which technique should I use for a set of matching arms?

Mould-blown, because a mould repeats a form. Ask for the elements to be made in one run, and say what must match: the form, not the colour or the wall, which still vary. Ask who keeps the mould so that spares match.

Does the technique change the lead time or the cost?

Our techniques guide says the technique shapes the lead time and the cost, and the processes the museums describe add stages, for example joining two parts hot, drawing and slicing canes, or grinding a surface. We found no published figure by technique and our own pages give different programmes, so ask the Murano partner for a programme by element type.

How do I name a technique in an FF&E schedule?

Name the technique for each element, with the reference sample, the colours, any position or thickness that matters, and the tolerance the workshop will work to. 'Murano glass pendant, blue' leaves all of that to the workshop. The wording on this page gives examples.

What is reticello?

A form of filigrana in which overlapping twisted canes form a criss-cross net. The Victoria and Albert Museum describes twisted canes with white cores forming a beaker, with a second twisted bubble fused inside it, and our journal says a small air bubble is trapped in each diamond.