Poly Crystalline

Polycrystalline (sometimes also called multicrystalline) solar panels are the most common because they are often the least expensive. They are the middle choice in the marketplace almost as good as single cell monocrystalline silicon panels but generally with a better efficiency than thin film solar panels. 
Polycrystalline cells can be recognized by a visible grain, a “metal flake effect”. The solar cells are generally square in shape, and may have a surface that looks somewhat like a mosaic. That’s because of all the different crystals that make up the module.