Earth's Core

The interior of the Earth is layered in concentric shells, much like the layers of an onion. The only part of the Earth that we have been able to observe is the Crust, which is composed of the Continental Crust and Oceanic Crust. The deepest hole drilled by humans on land reached less than 13 km.

Scientists have used seismic information from earthquakes to theorize about the structure of the Earth below the Crust. The generally accepted theory is that "The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core." 

Matter is found on Earth in four states: solid, liquid, gas and plasma. Plasma is found in lightning strikes. The energy is lightning is strong enough to heat matter and strip its electrons, forming plasma. Scientists have also created other forms of matter such as Bose-Einstein condensates and other states are theorized.

Based on what they know of matter, scientists extrapolate conditions in the inner layers of Earth. Heavy elements sink through the liquid and semi-liquid layers of Earth. Huge pressures force the core into a solid state.

Something Different
The inner core of the Earth is not formed from matter. At least, not matter as we know it. It is a sphere of high energy. The inner core isn't completely stable. It emits and ejects particles into the outer core. It is the source of most of the elements present on Earth.

The outer core is superheated by its contact with the inner core. Material ejected and emitted into the outer core from the inner core causes great turbulence. Some of this material pushes up into Lower Mantle.

The heated Lower Mantle affects the Upper Mantle.

How the Earth was Formed
The Earth started as a naked core. It emitted and ejected particles in the space around it. Some of those particles fell back onto its surface, beginning the building of the outer core. Eventually the outer core will become thick enough that it will form the Mantle. After enough time, the outer edge of the Mantle will cool and a crust will form.

It did not form from the gathering of dust particles. It formed from inside out.

Origin of the Core
The core came from the Sun, when the Sun was still a naked core.