“Although diamond jewelry was especially revered, late nineteenth-century Americans became increasingly interested in colored stones, both precious and semiprecious. The publication in 1890 of George Kunz's “Gems and Precious Stones of North America” heightened interest in such native American gems as tourmaline, opal, moonstone, and turquoise. By mounting an oval cabochon turquoise in a cage of yellow gold, Marcus & Company transformed a gemstone mined in Arizona into an imitation scarab, set with fiery demantoid garnet eyes. A gold loop at one end enabled the stone to be worn as a pendant.”
Prior to establishing Marcus & Co with his sons in 1892, German immigrant Herman Marcus (1828 - 1899) was employed by the prestigious New York City firms Tiffany & Co. and Black, Starr & Frost, and for a time partnered with the jeweler Theodore B. Starr. He was known for applying his knowledge of art and mythology to the jewels his company created. Upon his death in 1899 a remembrance published in “The Jeweler's Circular” stated "Few men who have ever been in the jewelry trade in New York have been more thoroughly versed in their business than was Herman Marcus." Marcus & Co. remained in business until 1942.
 "Marcus & Company: Pendant" (2001.239) In “Heilbrunn Timeline of Art History”. New York: The Metropolitan Museum of Art, 2000–. http://www.metmuseum.org/toah/works-of-art/2001.239. (September 2008)