The colors in natural brown diamonds are the result of internal parallel brown grain lines, which are caused by distortions of the crystal lattice. Ranging in tone from very light to very dark, the most popular varieties have medium to dark tones, with a warm, golden or reddish appearance. Often, greenish, yellowish, orangey, or reddish modifying colors are also present as well. Brown diamonds were popular in Roman times, but then fell out of favor for 1800 years. They regained popularity after the massive Argyle mine in Western Australia came on line 1985, and its owners launched a successful marketing campaign, in which they repackaged brown as “cognac,” “champagne” or “chocolate.”