Diamonds: Billions of Years in the Making

April, the month of rebirth or harvest, depending on which hemisphere you are in, is graced with the exquisite diamond as its birthstone.

Adopted from the Greek word adamas, meaning invincible, diamonds have accumulated centuries of mythology around their cold, sparkling fire. Romance, power, greed and even magic have all become entwined with their story. In the modern era, De Beers' 1948 “Diamonds are forever” campaign cemented their association with enduring love and commitment rings.

Diamonds are between 1 billion and 3.5 billion years old

Most natural diamonds formed around 150–250 kilometres beneath the Earth's surface, while some originated at extraordinary depths of up to 800 kilometres. They occur as transparent, translucent and opaque crystals and in a surprising range of colours. Trace impurities play their part: nitrogen can influence yellow tones, while boron is responsible for blue.

Among the fairest are the Type IIa Golconda diamonds. The historic Golconda region of India produced some of the world's most celebrated stones, renowned for their exceptional purity. Type IIa diamonds contain remarkably pure carbon and account for less than two percent of natural diamonds. The famous Koh-i-Noor is among the great diamonds associated with the region.

From lightning bolts to 58 facets

Long before their geological origins were understood, diamonds inspired much more imaginative explanations. Ancient Hindus, finding diamonds washed out of the ground after thunderstorms, believed bolts of lightning had created them. Elsewhere they were imagined as fragments of stars and attributed with healing, protective and magical powers. Across cultures, diamonds became associated with strength, courage and clarity.

Their appearance has evolved just as dramatically. Early diamond cutting produced rudimentary point and table cuts before cutters developed rose cuts, old mine cuts and old European cuts. In 1919, Marcel Tolkowsky's work on the proportions of the round brilliant helped establish the modern 58-facet diamond familiar today.

Diamonds: Your Strength & Stay

For all their mythology and glamour, perhaps the enduring appeal of natural diamonds comes back to their extraordinary beginnings. Formed deep within the Earth billions of years ago, their hardness and brilliance have made them symbols of strength, purity, love, abundance and perseverance.

As April's birthstone, the diamond is a fitting emblem for both rebirth and endurance — something ancient, resilient and still capable of extraordinary light.