Gold, Enamel, Diamonds
The Victoria & Albert Museum
It was (and still is) common practice for sovereigns to present rings (or boxes) which featured their portrait or cipher as a symbol of friendship or as a reward for loyal service. As we can see, this sparking ring bears the cipher of Louis-Philippe of France (reign: 1830-48).
Louis-Philippe was always quick to reward loyalty. He had many detractors as the last member of the Bourbon monarchy to reign in France. Plagued by troubles, Louis-Philippe abdicated as part of the 1848 Revolution. Napoleon III rose to power immediately after.