This picture is of Miss Cathleen Nielson, wife of Reginald Claypoole Vanderbilt. From the 14 Apr 1903 issue of the San Francisco Call newspaper, available through the Library of Congress’ Chronicling America collection.
The article describes the upcoming wedding festivities, but notably, describes the jewels that Cathleen received as wedding gifts from family members, including: a tiara and collar of diamonds from Mrs. Vanderbilt (i think this is Reginald’s mom, Alice) — a chain composed of diamonds and rubies from Miss Gladys Vanderbilt, Reginald’s sister — a tiara of emeralds and diamonds and brooches of diamonds and emeralds from her mother — a stomacher of diamonds from Mr. & Mrs. Alfred G. Vanderbilt, Reginald’s brother and sister-in-law — a diamond and emerald pin from Mr. and Mrs. Henry Payne Whitney, Reginald’s brother-in-law and sister — a diamond and emerald pin from Mr. & Mrs. Frederick W. Vanderbilt, Reginald’s uncle and his wife
from the article “...it is said the jewels are valued at a quarter million dollars. Special officers are watching the gifts night and day.” I bet they were!