Molten rock material that originates in the lower part of the Earth's crust, or mantle, where it reaches temperatures as high as 1,000°C/1,832°F. Igneous rocks are formed from magma. Lava is magma that has extruded onto the surface.
The flag may have been based on that of Schwyz, one of the original cantons of the Confederation. While the national flag is square, a rectangular flag is used on Swiss lakes and rivers. Effective date: 12 December 1889.