Russian alexandrite was named after Tsar Alexander II of Russia, who was the ruling monarch of Russia at the time of its discovery. The story goes that in 1830, a mineralogist named Nils Gustaf Nordenskiöld discovered a new gemstone in the Ural Mountains of Russia. He sent a sample of the gemstone to the Imperial Academy of Sciences in St. Petersburg, where it was identified as a new variety of chrysoberyl. The gemstone's unique color-changing properties, which Nordenskiöld described as "emerald by day, ruby by night," caught the attention of the Russian royal family.

In honor of Tsar Alexander II, the gemstone was named "alexandrite" and quickly became a favorite among the Russian nobility. The tsar himself was said to be particularly fond of the gemstone and gave several pieces of alexandrite jewelry as gifts to members of his family and court. The popularity of alexandrite in Russia helped to establish its reputation as a rare and highly prized gemstone, and the name "alexandrite" is still used today to refer to this unique variety of chrysoberyl.

Russian alexandrite is rare, beautiful, and sought after for several reasons. First, it is found in only a few locations in Russia, and the mines are no longer active. This means that the supply of high-quality Russian alexandrite is extremely limited, making it a highly valuable gemstone. Second, Russian alexandrite exhibits a unique and mesmerizing color change effect, which is caused by the presence of chromium in the crystal structure. The color change can range from green to blue-green in daylight or fluorescent light, to a reddish-purple or pink in incandescent light. The color change effect is so pronounced that it can sometimes be observed even in the shadows.

Russian alexandrite is a variety of the mineral chrysoberyl and has the chemical formula BeAl2O4. It is a beryllium aluminum oxide and has the same chemical composition as ordinary chrysoberyl. However, what sets Russian alexandrite apart is the presence of trace amounts of chromium in its crystal lattice structure. It is the presence of chromium that gives Russian alexandrite its unique color-changing properties. When exposed to different types of light, the chromium ions in the crystal lattice absorb different wavelengths of light, causing the gemstone to change color. The presence of chromium is a defining characteristic of this rare and valuable gemstone.

The combination of rarity and color-changing properties makes Russian alexandrite highly desirable among gem collectors and enthusiasts. Additionally, its historical significance as a gemstone named after Tsar Alexander II adds to its allure.

Here are some of the famous Russian Alexandrites:

1. The Alexander Pushkin Alexandrite: This 30.16-carat alexandrite was named after the famous Russian poet and writer Alexander Pushkin. It was discovered in the Ural Mountains in the 19th century and is now part of the collection of the Fersman Mineralogical Museum in Moscow.

2. The Imperial Alexandrite: This alexandrite was discovered in the 19th century and was owned by the Russian Imperial family. It was cut into a 65.08-carat gemstone and is now part of the Smithsonian Institution's collection in Washington, D.C.

3. The Malyshev Alexandrite: This 121.65-carat alexandrite was discovered in the Ural Mountains in the early 20th century. It is named after its owner, the Russian mineralogist Lev Malyshev, and is now part of the collection of the State Hermitage Museum in St. Petersburg.

4. The Sauer Alexandrite: This 10.12-carat alexandrite was discovered in the Ural Mountains in the 19th century and was named after its owner, the Russian jeweler Karl Fabergé's workmaster, Andreas von Sauer. It is now part of the collection of the Walters Art Museum in Baltimore.

5. The Tolstoi Alexandrite: This alexandrite was discovered in the Ural Mountains in the late 19th century and was named after its owner, the Russian writer Leo Tolstoy. It was cut into a 5-carat gemstone and is now part of the collection of the Fersman Mineralogical Museum in Moscow.