Lulu Harrison makes glass the medieval way, with slightly worse ingredients

Most glass starts with sand that was dug up far away, refined and shipped. Lulu Harrison's starts with whatever is lying around. In London that has meant river sand, wood ash and the shells of quagga mussels, an invasive species that blocks water pipes and otherwise ends up in landfill.

On October 8th she won the QEST Sanderson Rising Star Craft Award, which comes with £25,000. It is at least her third prize for this concept. In 2023 she took a £2,000 sustainability award from QEST and Heritage Crafts, and in 2025 the Design Museum gave her the Ralph Saltzman Prize and a summer display.

The idea itself is fairly old. Harrison points to the forest glass of late medieval Europe, when glassmakers used the sand, trees and ferns around them because that was what there was. Her contribution is a modern supply of rubbish.

It began with chemistry. While studying Material Futures at Central Saint Martins, she learned that calcium carbonate, the stuff of shells, is a main ingredient of ordinary soda-lime glass. She had lived in Cornwall and knew fishermen, so shells were easy to come by. From there she moved to the Thames, where the water company had mussel shells headed for the tip.

The result is called Thames Glass. It is green, and the colour comes from the local sand, not from an additive. So far it has become a carafe and tumbler meant to promote tap water, a small run of jugs, vases and glasses, and facade tiles developed with the architects Bureau de Change.

Since 2023 she has pushed the recipe further. Training with the glass historian Dr Chloe Duckworth, she tested batches of no more than three ingredients, all sourced around Newcastle, including wood ash and fish bones from a local restaurant. According to QEST, these melted at lower temperatures than a standard batch, and natural impurities did the colouring that metal oxides usually do.

The open question is scale. A glass that depends on one river's sand and one utility's mussels is, by design, hard to roll out. Her 2023 scholarship named scalable production as a goal, and the pieces sold since were one-offs. The new money is meant to develop the practice, which could mean more glass or simply more recipes. Harrison has said her aim is "showing the world how glass can be made in a different way". Three juries now agree.