Lest you fantasize that Marjorie Merriweather Post and the Cartier brothers had a kiss-kiss rapport full of daaaahlings and gin rickeys, you should know that their relationship was strictly professional.

“Cartier was a global corporation, so it didn’t have that deeply personal aspect,” says Liana Paredes, curator of “Cartier: Marjorie Merriweather Post’s Dazzling Gems,” a 50-piece lot of the D.C. socialite’s invaluable jewelry and photo frames made by the French design house now on display at Hillwood Estate, Museum and Gardens.

As one of Cartier’s most loyal U.S. customers, Post amassed a blinding collection from the 1920s through the 1960s, most of which remained in her estate when she died in 1973.

She was especially drawn to Cartier’s most avant-garde designs, and her purchases, when admired today, reflect milestones in Post’s life as well as the country’s history.

Hillwood Estate, Museum and Gardens, 4155 Linnean Ave. NW; through Dec. 31, $5-$15 suggested donation; 202-686-5807, hillwoodmuseum.org.

– 1909 –

Cartier opens its first U.S.-based jewelry store in New York City.

– 1914 –

Post, then 27, is named owner of Postum Cereal Co. after its founder — her father, C.W. Post — passes away.

– 1918 –

World War I ends, making way for the Roaring 20s.

– 1920 –

Fashions of the era reflect a woman of excess who is liberated and up for anything.

Post purchases a compact-lipstick combo and a gold vanity case, left, made for on-the-go-primping.

– 1929 –

The stock market crashes, sending the U.S. into an economic tailspin.

– 1931 –

Using insurance money she saved by putting some of her jewelry in a safety deposit box, Post founds the Marjorie Post Hutton Canteen in New York, which served more than 180,000 free meals in its first year and a half.

– 1936 –

Post’s then-husband, Joseph E. Davies, is appointed ambassador to the Soviet Union by FDR.

Post adopts a discreet and restrained image to project to the somber Soviets. She asks Cartier to fashion a necklace from two diamond bracelets and a sapphire broach, which she could break apart and wear for various occasions, shown right.

Post becomes the first female on the board of directors at General Foods (formerly Postum Cereal Co.).

– 1941 –

The U.S. enters World War II after the bombing of Pearl Harbor.

– 1950 –

During the war, materials like platinum were rationed to support armament manufacturing. With yellow gold now in vogue, Post commissions an amethyst and diamond necklace with matching earrings, left.

– 1960 –

As Post’s social engagements dwindle, she spends time relaxing in Palm Beach, Fla., where she vacations during the winters and is considered a grande dame. She adapts a seaside resort aesthetic, opting for turquoise drop earrings, one of her last pieces from Cartier, shown right.

– 1973 –

Post dies at the age of 86, leaving behind a massive collection of French and Russian art and jewelry.

Images from Hillwood Estate, Museum and Gardens. Compact-lipstick from Eleanor Close Barzin.