I would like to know if steel is basically a very dense crystal, or if it is a different atomic structure
Steel Crystalline Structure
Steel is made of billions, trillions of very small crystals. This is true of most metals. In order to see the crystal structure of steel, you usually need to cut a sample of it, grind and polish the cut face smooth, then etch the steel with a mixture of nitric acid and alcohol. Without polishing and etching the crystals aren't visible- it just looks like smooth solid metal. Also, in most cases the crystals are small enough that you need a microscope to see them clearly after etching.
Steel is crystalline. In general the bigger the crystals the better.
