French submarine Améthyste (S605)

The Améthyste is a nuclear-powered attack submarine of the French Navy, the fifth of the Rubis type. Her name is a pun on a precious stone (Amethyst) and the acronym AMElioration Tactique, HydrodYnamique, Silence, Transmission, Ecoute ("Tactical, hydrodynamics, silence and transmission improvements"). She is the first vessel to serve in the French Navy under that name.

She is a major upgrade upon the initial design of the Rubis type, and earlier units have since been refitted to meet her standards.

The Améthyste also took part in Operation Allied Force, the 1999 bombing campaign over Yugoslavia, by protecting the NATO aeronaval group. Along with the Rubis, she was one of the two submarines that interdicted the Kotor straits to the Serbian Navy, thus effectively forbidding their use. She also gathered information for the coalition.

The submarine Améthyste was part of the French naval task group led by the Charles de Gaulle that departed Toulon on 30 October 2010 for a four-month deployment to the Mediterranean Sea, Red Sea, Indian Ocean. and Persian Gulf. The task group commander, Rear Admiral Jean-Louis Kerignard, defined force's mission as follows:

"The force would help allied navies fight piracy off the coast of Somalia and send jets to support NATO in the skies above Afghanistan."

Once on station, the Charles de Gaulle carrier task group joined two U.S. Navy carrier strike groups led by the Nimitz class aircraft carrier aircraft carriers USS Abraham Lincoln (CVN-72) and USS Harry S. Truman (CVN-75) operating in the Persian Gulf. Subsequently, between 7–14 January 2011, the French carrier task group led by the Charles de Gaulle participated with bilateral naval exercise, code named Varuna 10, with the Indian Navy. Indian naval units participating in Varuna 10 included the aircraft carrier INS Viraat (R22), the frigates INS Godavari (F20) and INS Ganga (F22); and the diesel-electric submarine INS Shalki (S46). Varuna 10 was a two-phase naval exercise, with the harbor phase taking place between 7–11 January and the sea phase between 11–14 January in the Arabian Sea.