JOHN C. DEMMERT was born in Germany around 1857. His father Christian Demmert, was a jeweler, and with uncle August Demmert controlled South African diamond imports in Central Europe at one time. He came to America in 1875, and became a citizen in 1880, taking a position with a jeweler in Philadelphia. He married Bertha Noll about this time. Going into business for himself, he operated a store in Phoenixville PA. By March of 1890 he had purchased the jewelry store of Charles Stakeman, at 23 East State Street in Trenton NJ. He took a break from the Jewelry business in 1895 and moved to Medford NJ, where he operated a hotel through at least 1898. He came to Camden in 1904.

A recognized expert in diamonds, John C. Demmert opened up a jewelry store at 504 Federal Street upon arriving in Camden. He remained at that location through at least 1929, before moving his shop to 216 Broadway.

During his tenure in the jewelry business, John C. Demmert was robbed six times. On March 7, 1933 he was mugged outside his home at 110 North 7th Street. His family believed that a blow to the abdomen during this incident contributed to his death three years later, on August 13, 1936. He was survived by his wife Bertha, sons Howard and Harold, and daughters Dorothy and Viola. John C. Demmert was buried at Laurel Hill Cemetery in Philadelphia PA.

Bertha Dorothy and Viola Demmert were still living at 110 North 7th Street as late as 1947. Viola Demmert had remained in the jewelry business, conducting a shop at the 110 North 7th Street address selling gold, diamond and tungsten jewelry, while Dorothy Demmert was at that time a teacher at the George Washington Elementary School in the Cramer Hill section of Camden..

Camden Courier-Post - August 14, 1936