It wasn't until the late 20th century that yellow diamonds began to gain popularity once again. In 1987, the Argyle mine in Australia started producing large quantities of yellow diamonds, leading to a resurgence in interest in these rare stones. Today, yellow diamonds are considered one of the most valuable and desirable colored diamonds on the market. Yellow diamonds are extremely rare, accounting for only around 0.1% of all diamonds mined worldwide. The intense yellow color of these stones is caused by the presence of nitrogen molecules in the crystal structure. The more nitrogen present, the deeper and more vibrant the yellow color. Most yellow diamonds fall into one of two categories: canary yellow or fancy yellow.