Mineral T Shirt

Around 2.5 billion years ago iron-rich seawater reacted with primordial microorganisms to form the basic ingredients of limonite. Layers of sediment from this seawater were deposited into the Earth’s crust and mantle, creating banded rock formations of contrasting orange, yellow, silver and brown colours.

Limonite is a type of iron oxide that forms when other minerals like hematite, pyrite and goethite combine. Over time the iron-rich layers of the banded rock formations were exposed to weathering. It caused them to dissolve and forge back together, creating limonite. Alongside hematite and magnetite, limonite is one of the three major ores mined for the extraction of iron. It’s often found lodged in cave walls, in iron-rich rocks and in marshes and bogs. 

Evidence of prehistoric humans working with limonite dates back to the Upper Paleolithic. In its raw state the mineral produces shades of colour from yellow to brown, which is why it was scraped across cave walls 40,000 years ago to draw cool pictures. And it’s limonite that gives our Mineral T Shirt its yellow colour. The limonite pigment we’ve used to dye the t shirt is called Siena, after the Tuscan clay once used by Renaissance painters.

Our limonite pigment is collected from an area in northern Italy where galleries of karst caves have been eroded out of the mountains. Over thousands of years the area has seen a unique set of geological transformations, creating a landscape where the ‘marble mountains’ of the Apuan Alps sit next to the carbonate rocks of the Dolomites. Many of the caves were once filled with water, causing mounds of yellow Siena clay to deposit and build up.

The limonite clay is collected, refined, refracted, and turned into a clean powder. To make the t shirt we then add the mineral powder to a vat of water and submerge the whole garment – a process called garment dyeing. There are only two byproducts of this process. Sediment, and water. Both of which can go straight back into nature.

Most clothes today are piece-dyed, which means the fabric is dyed before it’s cut up and sewn together. Garment dyeing requires more time and more care, but it creates softer fabrics with softer colours. And it means that rather than harsh chemicals, we only need to use heat, time and pressure for the colour of the limonite to stick to the t shirt.

Nearly all the colour you see in clothing today will have been created with petroleum-based dyes. But colour in clothing existed long before the chemical dyeing industry was invented. So we’ve gone back to the colour palette of early man. Because each t shirt is made using minerals made by nature, you might find small differences in colour across it. And because it’s garment dyed, every t shirt has a pre-worn look.

To add to the softness of the t shirt, we don’t just garment dye it in minerals, it’s also made with a blend of 53% hemp, 44% organic cotton, and 3% elastane for stretch, giving it a soft feel and a nice weight.

We tend to think of the colour on our clothes as one thing. Something uniform, bold, and often bright. But this is created using highly synthetic processes. And the colours that nature produces aren’t like that. There are no crazy colours on cave walls because they simply didn’t exist. Dyeing clothing in minerals, rocks and soils is designed to help us rethink how colour can be made.