Nanodiamond is widely used in advanced industrial and biomedical applications due to its unique combination of hardness, chemical stability, and biocompatibility. In polishing and precision machining, nanodiamond suspensions are used to achieve ultra-smooth surfaces on hard materials such as optical lenses, semiconductors, and hard disk drives. Its low toxicity and ability to be functionalized make it valuable in drug delivery systems, where it can carry therapeutic agents into cells with high efficiency. Nanodiamond is also explored in imaging and sensing, serving as a fluorescent probe in biological systems. In composites, it enhances mechanical strength, thermal conductivity, and wear resistance when added to polymers, metals, or ceramics. Additionally, it shows promise in quantum sensing and electronic devices due to its nitrogen-vacancy center properties.