Strengths and drawbacks come in pairs
Almost every advantage of diamond has a matching limitation, and that is typical of extreme materials. The same atomic structure that gives diamond its remarkable behavior also explains where it falls short. Looking at each property alongside its drawback gives a more accurate picture than a list of superlatives.
Extreme hardness
Advantage: Diamond is the hardest common material, so it can cut, grind and polish almost anything else, and it resists abrasive wear better than most alternatives. This is why it dominates in abrasives, saw segments and tools for abrasive workpieces.
Drawback: Hardness is not toughness. Diamond is brittle and can chip or cleave under impact or when poorly supported. Reading about fracture toughness alongside hardness helps explain why very hard materials are often used as small, well-supported inserts or coatings rather than as large solid pieces.
Thermal conductivity
Advantage: Diamond conducts heat extremely well, often several times better than copper at room temperature. That helps spread heat from lasers and power electronics and keeps cutting edges cooler. Different grades vary, and impurities and defects reduce the conductivity.
Drawback: High-quality diamond for thermal use is expensive, and joining it to other materials is demanding. Differences in thermal expansion and the quality of the bond between layers can limit the benefit in a real assembly.
Optical transparency
Advantage: Pure diamond transmits light over a very wide range of wavelengths, from parts of the ultraviolet through the visible and deep into the infrared. Together with its strength, this makes it useful for windows exposed to powerful lasers or aggressive environments.
Drawback: Optical-grade pieces are costly, available in limited sizes, and sensitive to impurities that absorb light. Large windows are harder to make than small ones.
Chemical stability
Advantage: Diamond resists most acids, bases and solvents at ordinary temperatures, which suits it to corrosive settings and electrodes.
Drawback: It is not unlimited in this respect. In air it begins to oxidize at elevated temperatures, and at high cutting temperatures it can react with iron, nickel and similar metals. That is a main reason it is rarely chosen for machining steel.
Tunable electrical behavior
Advantage: Pure diamond is a very good electrical insulator, and boron doping can turn it into a conductor or semiconductor. Researchers see this range as useful for electrodes, sensors and some experimental electronic devices.
Drawback: Doping and making large, uniform, defect-free wafers is difficult, and other semiconductors are far more developed commercially. Diamond electronics should be regarded as an area of ongoing development.
Controllable synthetic form
Advantage: Because it is manufactured, diamond can be produced as grit, films, plates or compacts with chosen properties, and supply does not depend on mining.
Drawback: Production is energy-intensive and requires specialized equipment. Quality varies between producers and grades, so specifying exactly what you need is important.
Comparing it with alternatives
Other superhard options, including cubic boron nitride, silicon carbide and tungsten carbide, each give up some hardness or thermal performance but offer advantages such as better behavior on steel, lower cost or greater toughness. No single material wins on every measure. A practical selection starts from the actual problem, such as abrasive wear, heat or corrosion, and compares candidates against it.
Keeping expectations realistic
The best way to use a list of advantages is as a set of hypotheses to test. Diamond is not simply “better”; it is better at certain things under certain conditions. When a source praises its hardness without mentioning brittleness, or its conductivity without mentioning cost and bonding, treat that as a sign that something is missing from the discussion.