Diamond, the hardest known material is pure carbon, crystallized under a very high pressure and temperature. In nature, such an environment exists only at depths of 150 to 200 km below the surface of the earth. Volcanic eruptions drive the diamond bearing rocks called “Kimberlite” and “Lamproite” to the surface of the earth where the diamonds can be extracted.

Among the various types of jewels in which the diamond has played a leding, none is of greater human interest than the smallest of all the diamond rings given to pledge ones love and to seal a marriage. Seen in historical perspective, the modern engagement ring is the most recent link a long chain reaching far back in to the past. Rings as forms of adornment date back several millennia, But the earliest surviving writings on rings as tokens of love are from the roman playwright Plautus in the second century B.C.E,10 and wedding rings are known because of inscriptions that occasionally recorded the marriage contracts sealed in the presence of the emperors image.