👉 Boulangerite is a rock-forming mineral that has been found in various locations around the world, primarily in the United States and Canada. It is a type of orthogneiform quartzite, which is a type of quartzite with a single layer of quartz crystals arranged in a bicolored pattern. The term "boulangerite" comes from the French word "boulanger," meaning baker, as it was first discovered by a baker named Jean-Baptiste Boulanger