QQQ has huge tech exposure, but it is not a 'tech fund' in the pure sense either. The fund's arcane weighting rules further distance it from anything close to plain vanilla large-cap or pure-play tech coverage.
During the time when Earth was forming and was in a molten state, heavy materials like iron and nickel sank to the center of the Earth's mass and lighter materials floated to the surface of the mass. The very center of what we call the core, is solid in the middle because of the increased pressure in that region.
After a few hundred million years the temperature of Earth reached 2,000C - the melting point of iron - and Earth's core was formed. At this point much of the Earth was molten and there may have been a magma ocean at the surface. Gradually the Earth cooled and the planet settled out into a core, mantle and crust.