Question: What American luxury jewelry and specialty retailer did Jean Michel Schlumberger work at?

Context paragraphs:
Jean Schlumberger (jewelry designer): Jean Michel Schlumberger (June 24, 1907 – August 29, 1987) was a French jewelry designer especially well known for his work at Tiffany & Co.

YVEL: YVEL (pronounced E-vel) is a privately held luxury jewelry company in Jerusalem.  Founded and owned by Orna and Isaac Levy, the company is best known for its pearl jewelry.

Alor (company): Alor is an American luxury jewelry, watch and lifestyle brand founded by Jack and Sandy Zemer in 1979.  Alor specializes in designing, creating, and manufacturing 18kt gold, diamonds and cable pieces.  It is headquartered in San Diego, California.

Eclarity: eClarity Pte Ltd is an online specialty retailer of jewelry.  eClarity was registered in year 2000 and today owns an online diamonds database with more than 20,000 pieces of diamonds, 400 designs of wedding bands, and other jewelry.  eClarity is based in Singapore, and competes with traditional jewelry retail chain stores, and global online retailer stores such as ringsberry and Blue Nile Inc..  The key feature of eClarity is customization of engagement ring, wedding jewelry, and wide range of online database of diamonds.

Kuhn &amp; Komor: Kuhn & Komor, also known colloquially as "K&K", was a Hungarian multinational luxury jewelry and specialty retailer, having headquarters in Shanghai, China.  K&K produced jewelry, sterling silver, china, crystal, stationery, and personal accessories.  K&K was renowned in East Asia for its luxury goods, also being called the "Asprey of Asia."

Jean Michel (poet): Jean Michel (c. 1435–1501) was a French dramatic poet of the fifteenth century known for revising and enlarging the passion play "the Mystery of the Passion" (French title "Le mystère de la passion") by Arnoul Gréban.  There are three Michels mentioned in connection with this work.  There is Bishop Jean Michel of Angers (died 1447), a "Maistre Jehan Michel" who was first physician of King Charles VIII (died 1495), and the physician to the dauphin, son of Charles VIII (died 1501).  The bishop is considered the least likely candididate for being the poet, having died too early, while the physician to the dauphin is the most likely, due to the latter also being associated with Angers, and the work being produced for the first time in its new shape at Angers in 1486.

Kristall Smolensk: Kristall Smolensk is a Russian worldwide luxury jewelry retailer, headquartered in Smolensk, Russia.  Kristall Production Corporation was founded in 1963 for the development of the diamond polishing industry in Russia.  The company has become the major polished diamonds manufacturer in Europe, and one of the leading diamond centres in the world.  Kristall Smolensk diamonds is a sightholder of two prestigious rough suppliers in the world, De Beers and Alrosa.

Marcus &amp; Co.: Marcus & Co. was an American luxury jewelry retailer from 1892 to 1962 in New York City.

Tiffany &amp; Co.: Tiffany & Company (known colloquially as Tiffany or Tiffany's) is an American luxury jewelry and specialty retailer, headquartered in New York City.

Blue Nile (company): Blue Nile is an online specialty retailer of fine jewelry.  Blue Nile was founded in 1999 and today is the largest online retailer of diamonds.  Blue Nile is based in Seattle, Washington and competes with traditional jewelry stores such as Tiffany & Co., and online retailer stores such as James Allen, Belgium Diamonds, Ringsberry.com.

Supporting paragraphs: Jean Schlumberger (jewelry designer) Tiffany &amp; Co.
Answer: Tiffany & Company