Dermoscope is a skin surface microscope. A combination of light, magnification and cross polarization, makes light penetrate deeper and stops reflection and scattering. This helps analyse the deeper pattern of the mole, which would be impossible when viewed though unaided eye.
Mole Normal View
This mole with some light and magnification looks ordinary. It is very difficult to know if this has any worrying features as the ABCDE criteria is negative( no asymmetry, border regular, one colour, 4mm diameter and not enlarging)
Now much clearer, this mole has some features that needs to be followed up or removed if it cannot be reliably followed (mole map or mole mapped)
Normal close up view of a melanoma, this mole will look ordinary when this is not photographed with a macro lens with light and magnification. You can still clearly see the irregular margins and blue shades.
This is the dermoscopic view of the above mole. You can see more details and melanoma specific criteria. Once you see this nasty picture this needs to be cut out ASAP. This was a breslow 1mm thick melanoma cut out by me.