Yes, Frances Pont-Aven Gneiss can be used in a bathroom. Gneiss is a type of metamorphic rock that is known for its durability and resistance to heat and moisture. It is often used as a natural stone for countertops, tiles, and other surfaces in bathrooms and kitchens. The Pont-Aven Gneiss, specifically, is a popular material for its beautiful patterns and colors, making it suitable for bathroom applications such as vanity tops, flooring, or wall cladding. However, it is important to properly seal and maintain the gneiss to prevent any potential water damage or staining.