Tank Obus — Cartier Paris · Luminous Indexes, circa 1930

Identifying details

• CabochonCabochonA stone polished into a smooth dome without facets. In watches, cabochons can decorate the crown or dial; the term describes the cut rather than a particular gemstone. crown

  Winding crown set with a cabochonCabochonA stone polished into a smooth dome without facets. In watches, cabochons can decorate the crown or dial; the term describes the cut rather than a particular gemstone., typically a blue sapphire.

• European Watch & Clock Co. movementMovementThe working mechanism inside a watch or clock.

  Movement supplied or signed by the European Watch & Clock Co., the Cartier–Jaeger joint venture.