Norwegian design studio Ment has created handcrafted tableware for Snøhetta's recently completed underwater restaurant in Norway using sand and minerals taken from the surrounding coast.

Sisters Ingvild and Sidsel Forr Hemma, who make up Ment studio, worked with Under's head chef Nicolai Ellitsgaard for the past year to design, research and test a set of tableware for the restaurant's 18-course menu.

Labelled as the "world's largest underwater restaurant", Under was completed last month. Snøhetta designed the monolithic structure to plunge into the sea from a rocky shoreline in the remote village of Båly, Norway.

Together, the Forr Hemma sisters designed and manufactured approximately 500 items by hand in their studio in Fåberg, using 17 unique designs with variations in size, material and colour.

Objects include water jugs, toothpick holders, coffee and tea cups, milk jugs and sugar pots, as well as an array of bowls and plates for the food.

"The focus on nature and the underwater-concept was important in this project, and the inspiration comes from the seashore beside Under," Ingvild told Dezeen.

"The concepts for the products have been developed in relation to Snøhetta's fantastic overall concept that they have developed for Under."

Ingvild and Sidsel used natural materials such as porcelain, stoneware, wood and clay to create the tableware, as well as sand taken from the beach at Båly to achieve a rough, earth-like surface.

While some products were first cast and later processed by hand, others were initially shaped by hand with different types of clay.

For the colour palette, the sisters took inspiration from the seaweed, sand and coastal rocks found in the area around the restaurant, focusing on using Norwegian minerals to give each piece its distinct hue.

"The Norwegian coast has very unique colours and species found only in this area because of the cold climate," Ingvild continued. "Soft tones of brown, grey and green and beautiful textures are elements we wanted to adopt in our design for Under – choosing materials that give the collection a raw and natural feel."

They researched and developed their own recipes using iron pigments, made by processing iron oxides from natural magnetite taken from the area of Nordland in Norway. According to the designers, this use of natural magnetite grants "very exciting and varied results".

The shades of colour in particular are "impossible to control" with the chosen technique yielding different results in each of the products, mirroring organic processes found in nature.

Established by the Forr Hemma sisters in 2012 in Fåberg, Norway, Ment aims to educate the public about the quality of handmade products, and the craftsmanship and knowledge that is involved in their making.

According to the duo, Ment was born when they both realised that they wanted to create products with meaning, and not just contribute to the increasing consumerism.