Sen. Sinema took ceremonial oath on an Arizona law book

PHOENIX (FOX 10) -- Sen. Kyrsten Sinema took her ceremonial oath of office on an Arizona law book.

In photos taken by Getty Images, Sinema was seen, during a mock swearing-in ceremony presided by Vice President Mike Pence, being sworn in on a book named "Arizona Compiled Laws".

Sen. Sinema was elected in November's midterm election, defeating GOP candidate Martha McSally. McSally was later appointed to the Senate, taking a seat that was held by John McCain prior to his passing.

According to FOX News, Sinema is one of a number of lawmakers who used historical texts and family heirlooms during the swearing-in ceremonies. McSally, during her ceremony, was sworn in using a bible that was recovered from an unknown sailor aboard the USS Arizona. The bible was reportedly on loan from the University of Arizona. Accoridng to the Pew Research Center, Sinema says she is religiously unaffiliated.

At least two lawmakers, according to FOX News, took their ceremonial oaths using the Quran. Ilham Omar, a Democratic lawmaker from Minnesota, used her grandfather's Quran, while Rashida Tlaib, a Democratic lawmaker from Michigan, used an English translation of the Quran that was owned by former President Thomas Jefferson.

According to the Pew Research Center, Christians are overrepresented in Congress. Data provided by the group shows 88.2% of all members of Congress are affiliated as belonging to various factions of Christianity, compared to 71% of U.S. adults.

FOX News contributed to this report. FOX 10 reported on this story from Phoenix.