Microcrystalline Diamond (MCD) (grains ≥ 1 µm) and Nanocrystalline Diamond (NCD) (grains 20-900 nm) coatings have been grown using Microwave Plasma Chemical Vapor Deposition (MPCVD), exciting H2/CH4 gas, via microwave power, in evacuated chambers, producing C atoms, bonding on surfaces with sp3 C atoms diamond bonds. Alternatively, MCD/NCD films have been grown via Hot Filament Chemical Vapor Deposition (HFCVD), using ~2200°C hot filaments, cracking CH4 into C atoms. Auciello-Gruen-Krauss developed (1990s) a transformational MPCVD process, growing unique multifunctional Ultrananocrystalline Diamond (UNCDTM) coating (3-5 nm grains), using patented Ar/CH4 gas mixture. Subsequently, Auciello’s group developed HFCVD process with Ar/CH4/H2 and H2/CH4. Gases flowing though filaments heated to ~2300°C. UNCD coatings exhibit unique multifunctionalities, enabling new industrial/high-tech/medical products, namely: 1) UNCD-coated pump seals/bearings/AFM tips (marketed worldwide since 2009); 2) unique electrically conductive Nitrogen atoms-grain boundary incorporated N-UNCD-coating on commercial graphite / copper anodes anodes, enabling superior stable capacity energy/safer Li-ion batteries; 3) Unique water corrosion resistant/electrically conductive Boron-doped B-UNCD-coated metal electrodes, purifying water, via viruses/pathogens’ killing by Ozone (O3) molecules generation.; 4) Best biocompatible UNCD coating (made of C atoms in human DNA/cells life’s elements) enable new medical products (e.g., UNCD-coated Si-microchip implanted on retina, to restore partial vision to blind people; UNCD-coated Dental Implants (DI), eliminating oral fluids corrosion of metal-DIs (clinical trials in progress),; 5) UNCD-coated magnet, outside eye, attracts injected biocompatible superparamagnetic nanoparticles, reattaching retina on eye’s wall; 6) superhydrophobic UNCD coated polymer-valves, drain inner eyes’ fluid of people with glaucoma, inhibiting blindness.