The largest alexandrite crystal weighing 5724 grams was discovered in the Takovaya district of the Ural mountains in 1840. This deposit continued to be mined for over 60 years and produced both emeralds and alexandrites until the turn of the century. Alexander Fersman, a noted Russian gemmologist reported, that 2,000 kilos of rough alexandrite in comparison to 20,000 kilos of rough emeralds were mined. This deposit was the only source of alexandrite for many years and the Russian stones set the original standard for this extremely rare and valuable gemstone. The discovery of fine Brazilian alexandrite in 1987 reset that standard. While the Russian stones display a better green in daylight, many experts agree that the purple reds of the Brazilian stones are clearly superior.