The earth is made of mostly rock because the crust is rock and the inside such as the core is molten rock such as lava.
rocks
rocks
rocks
Gas
Uranus is a gas giant, it has a rocky core but is mostly gas.
Mars is mostly rock
Jupiter is mostly made out of gas not rock.
pluto is made of heap of rock.it is not made of gas.
the earth is made from rocks although the core is burning gas
The Earth and the Moon are not made mostly of gas but the Sun is.
The planet Saturn is almost entirely made of gas. It is not for nothing that it is known as a gas giant.
The earth is made of rock. It's sometimes called the lithosphere, and litho means rock. A lot of the rock in the middle of the planet is molten, but liquified rock is rock just the same. The earth has an atmosphere, but it is not a "gas planet" in that sense. We look at the structure of the earth in geology and geophysics. And most folks associate geologists with rocks.