Laykin jewels were often borrowed by Hollywood's leading producers, directors, costume designers and even stars themselves throughout the 1930s - 1990's.  

Several films reflecting the Film Noir genre included Laykin jewels adorning their heroines and femme fatales.

In 1947 - 1948; Laykin et Cie was commissioned to produce the central jewel in the love triangle and murder story featured in "Impact". (Released by United Artists in 1949)

Leading actress Helen Walker plays beautiful, lustful and murderous Irene Williams and is presented in one of the films key scenes with a custom made platinum and diamond Laykin brooch featuring 20 cts of round and baguette diamonds representing two intertwined hearts with the femme fatales' initials included.    The same design is featured embroidered on the shirt of her lover as the story develops.

This striking glamour photo of Miss Walker features the custom designed Laykin brooch along with a platinum and diamond Laykin bracelet, ring and earrings and even a solid gold Laykin et Cie cigarette holder; de rigueur of the period.

Link to 1949 Impact Feature Film:  https://www.youtube.com/watch?v=53yLh6A1CIY

Excerpt from Wikipedia:  

Regarding Early Hollywood Product Placement

In the 1940s, it was still uncommon for brand name products to be seen in movies, but this was a notable exception. A Bekins moving van is prominent in several scenes. The movie trade paper Harrison's Reports typically called attention to cases in which such products appeared on screen, and always took a stand against that practice. Although its review did not mention Bekins, the Harrison's review noted "advertising plugs worked in for such products as Pabst Blue Ribbon beer, Raleigh cigarettes, Coca-Cola, Mission Orange soda pop, Mobil gasoline, oil and tires, Gruen watches, and the trade name Rexall."

In addition, Laykin et Cie (of I. Magnin & Co) is featured in the opening credits. Laykin et Cie was a leading West Coast jeweler during the period with an important salon in San Francisco during the time the movie was shot in 1948. In the opening scenes, Donlevy's character Walter Williams presents his wife with a custom Laykin et Cie intertwined diamond double heart brooch with the initials "IW" (for Irene Williams) which was produced for the film. Throughout the film, Irene Williams continues to wear various Laykin et Cie jewels of the period.

The Plot

The San Francisco-based millionaire industrialist Walter Williams (Brian Donlevy) has a younger wife, Irene (Helen Walker), who is trying to kill him with the help of her young lover, Jim Torrance (Tony Barrett). After Walter and Irene make plans to drive to Lake Tahoe, Irene feigns illness and asks Walter to instead give Torrance, who is pretending to be Irene's "cousin" from Illinois, a lift to Denver, allowing Torrance a chance to murder Walter en route. The plan falls apart when Williams survives a hit on the head from the would-be killer. Attempting to flee the scene in Williams' Packard convertible, Torrance dies in a fiery head-on collision with a gasoline tanker truck. The body of Torrance is mistakenly identified as Williams. In the meantime, Irene has made reservations at a hotel in Oakland for her and her boyfriend to meet afterward, under the assumed names of "Mr. & Mrs. Jack Burns".

The wounded, dazed Williams falls asleep in the back of a moving van and ends up in the small town of Larkspur, Idaho. Using the name "Bill Walker", he gets a job as a service station mechanic and falls in love with Marsha Peters (Ella Raines), a young widow who is the station's owner. Meanwhile, the police arrest Williams' wife for his "murder". After Marsha eventually persuades Walter to go back to clear his wife, he is charged with murdering Torrance. Marsha enlists the help of kindly police detective Quincy (Charles Coburn) to prove Walter's innocence.