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.
Heavier elements like iron tend to sink toward the center or core of the earth. Lighter materials, the silicates, oxygen compounds and water have risen to become part of the crust. This action has created distinct layers within the earth and is still in process today. The Inner Earth is composed of three main parts; the crust, the mantle, and the core as shown in the diagram of the earth's interior below: The Crust - silicate rocks, primarily granite and basaltOceanic Crust - mostly basaltContinental Crust - igneous, metamorphic, and sedimentary rocks.