Crystal and Diamond

Among many types of crystals, diamond is one of the crystals which have formed from carbon. Therefore, diamond has many similar characteristics of a crystal.

Crystals

Crystals are solids, which have ordered structures and symmetry. The atoms, molecules or ions in crystals are arranged in a particular manner, thus have a long range order.  Crystals are naturally occurring on earth as large crystalline rocks, such as quartz, granite. Crystals are formed by living organisms too. For example, calcite is produced by mollusks. There are water based crystals in the form of snow, ice or glaciers.

Crystals can be categorized according to their physical and chemical properties. They are covalent crystals (e.g. diamond), metallic crystals (e.g. pyrite), ionic crystals (e.g. sodium chloride), and molecular crystals (e.g. sugar). Crystals can have different shapes and colors. Crystals have an aesthetic value, and also it is believed to have healing properties; thus people use them to make jewelry.  Moreover, people use crystals like quartz to make glass, clocks and some computer parts.

By definition, a crystal is “a homogenous chemical compound with a regular and periodic arrangement of atoms.  Examples are halite, salt (NaCl), and quartz (SiO₂). But crystals are not restricted to minerals: they comprise most solid matter such as sugar, cellulose, metals, bones and even DNA.”

Diamond

Diamond is a precious stone, and it is the most popular gemstone. Diamond is an allotrope of carbon. The carbon atoms are tetrahedrally bonded to each other to form the diamond lattice. Each carbon is, therefore, sp³ hybridized.  It is a variation of face centered cubic. The diamond lattice is made by three dimensionally dispersed and connected carbon atoms. So compared to graphite which has carbon atoms arranged into sheets, chemical bonds of diamond are weaker. Diamond is a transparent crystal. It is normally yellow, brown, gray or colorless, but because of the impurities sometimes it can have colors like red, violet, orange etc.

Diamond crystal has useful properties, which makes it more valuable too. It is the hardest material known. In the Mohs scale of hardness, it is ranked as to have a value of 10, which is the highest value. Hardness of the stone depends on its purity, crystalline perfection and orientation. Because of its hardness it is used to cut glass, and also as a gemstone to make jewelries.  Diamond has a high thermal conductivity which is ranging between 900–2,320 W·m⁻¹·K⁻¹. Diamonds can also act as semiconductors. Diamonds have exceptional optical characteristics which again makes it suitable as a gemstone.

Since diamonds are lipophilic, they can be extracted using oil. Further, it is hydrophobic. Diamonds are not very reactive. Diamonds are naturally formed in the Earth mantle at high pressure and high temperature. This process takes billions of years. However, now there is a synthetic process to produce diamond by mimicking the natural conditions.

What is the difference between Crystal and Diamond? • Diamond is a crystal. • Diamonds are the hardest crystal compared to other crystals. • Diamond has exceptional optical properties in contrast to other crystals. • Thermal conductivity is higher for diamonds than many other crystals. • Diamonds are expensive compared to many of the other crystals.