Phosphosiderite is a form of iron phosphate that can only be found in a few locations worldwide.
Iron phosphate is a chemical compound of iron and phosphate. Iron is a metal, phosphate is a group of atoms containing phosphorus and oxygen.
When both come together they form iron phosphate.
Phosphosiderite was once known as metastrengite but the name is no longer used.
Although phosphosiderite forms very small crystals in shades of red and pink it's found more often with a massive crystal habit.
Minerals that crystallise in this way grow tightly together to form one large shapeless mass.