Top 10 Famous Individual Gemstones Named After Rulers, Dynasties Or Members Of Royal Families

It was named after James Stuart (Prince of Wales), the son of James II. Before that the gem most probably belonged to Charles II. The stone was set in Queen Victoria's State Crown, on the front.

Named after King Louis XIV of France, he owned it

It was named after the rulers of the Mughal Empire (Indian dynasty). It bears a date indicating that circa 1695-1696 AD this emerald already existed.

It's the 4th largest blue sapphire in the world.

It was named after William Cavendish, 6th Duke of Devonshire, and is one of the world's largest uncut emeralds (weight: 277 g). In 1831, it was either gifted or sold by Emperor Pedro I of Brazil to William Cavendish, 6th Duke of Devonshire.

This "ruby" is actually a red spinel, believed to be ruby until 1851, hence its name. It was named after the ruler Timur, founder of the Timurid Empire. Timur (also known as Tamerlane), was a warlord of Turco-Mongol lineage.

The East India Company presented the Timur Ruby to Queen Victoria as a gift in 1851. It was set in a necklace for Queen Victoria in 1853. The gem is inscribed with the names and dates of some of its previous owners:
Timur
Akbar, 1612
Jahangir, 1628
Aurangzeb, 1659
Farrukhsiyar, 1713
Ahmad Shah Durrani, 1754
Maharaja Ranjit Singh, 1813
Maharaja Sher Singh, 1841
Maharaja Duleep Singh, 1849

Very cool is what this is.

It was named after Archduke Joseph August of Austria, Prince of Hungary and Bohemia, who was the diamond's first recorded owner. This colorless diamond is internally flawless. In 2012 it was sold to an anonymous buyer for US $21.4 M.

Named after Mexico’s ill-fated emperor, Ferdinand Maximilian Joseph. The ring was worn by him.

This "ruby" is, again, a large red spinel and not a ruby - it was wrongly identified as ruby centuries ago (before 1367 for sure), but spinel is a great gem, too. It still goes by the name "ruby" though. Tradition. The gem was mounted on the Imperial State Crown of England.
It was named after Edward of Woodstock (aka the "Black Prince"). The gem has been in the possession of England's rulers since it was given in 1367 to Edward of Woodstock (the "Black Prince"). Edward was the eldest son of King Edward III of England but the "Black Prince" died before his father and never became king.