Larvikite is a type of rock that comes from Norway. It is mostly made up of minerals called feldspar and nepheline. Have you ever seen a puzzle with colored pieces that fit together? Larvikite is kind of like that, with different colors and shapes that all fit together to make the rock.
One really cool thing about larvikite is that it can have a shiny, reflective surface. It is often polished and used for things like countertops, tiles, and even jewelry. Imagine looking at a mirror, but instead of seeing yourself, you see a piece of shiny, grey rock!
People have been using larvikite for a very long time. In fact, some ancient Norse myths talk about a magical stone called "the black sunstone" that was used to navigate ships in the ocean. While we don't know for sure if this stone was actually larvikite, it's possible that it was because of its shiny surface and the fact that it comes from Norway, which is where the Norse myths come from.
So, in summary, larvikite is a cool rock from Norway that is made of different shapes and colors, and can have a shiny, reflective surface. People have been using it for a long time, for things like countertops and jewelry, and it even shows up in ancient Norse myths.