Even though colored diamonds are very rare, brown diamonds of different shapes and styles are available aplenty in the market. In fact, due to their worldwide availability, brown diamonds are the cheapest colored diamond out there. This means brown diamond engagement rings are ideal for women who want to wear affordable fancy colored diamond rings. The elegant color and stunning look of brown diamond rings have considerably increased their popularity over the years. In fact, a number of brides prefer to settle for a brown diamond engagement ring instead of looking for other options. The distinct brown color of brown diamond rings is due to inner graining. Inner graining is usually caused by the structural non-uniformities inside the crystal lattice of a diamond. The common secondary colors found in the center stone of brown diamond rings are pinkish brown, orange-brown, and yellowish brown. Brown diamonds were actually very scarce before the Argyle mine in Australia started to produce them. However, small deposits of brown colored diamonds were used exclusively for industrial use before Australian Argyle mine started producing these diamonds. Australian Argyle mine continues to be one of the major producers of brown diamonds.