Two material innovators have developed a method to ‘grow’ stones which allows for all kinds of novel shapes for a material that is usually considered bulky and massive.
A 3D printed nylon structure is the basis for the development. This framework is placed into naturally occurring hot-springs, where it accrues a layer of off-white calcium carbonate. This is also known as calc, and is a principal ingredient of concrete.
In this way, the designers grew a whole range of objects – dishes, bowls and the like – that have a latticework frame and structure, and the physical properties of porcelain.
Growing, in this case, is a procedure that is copied from the natural process of calcium deposition. The developers, Thomas Vailly and Laura Lynn Jansen, studied mineral springs, where the warm, mineral-rich water quickly leaves a limestone-like covering on almost any solid object in the water. As the minerals are left on the pre-shaped nylon mesh, carbon dioxide is released into the atmosphere.
This also happens in your kitchen with hard water: white scales on the inside of a kettle are mostly calcium that is left over during heating. Here, the process is refined to grow a strong, rigid covering in exactly the areas decided upon by the designers.
The process is controlled to some extent, as the nylon mesh is inserted in water for set periods of time. Still, the process is natural, and growth can not be exactly determined. The designers don’t mind, saying the additive process, relatively uncommon in stone, is an interesting surprise.
Growing materials is gaining popularity: last year, an American team won a grant to grow building bricks from bacteria.