Georgiana was often referred to as "the beautiful Duchess of Devonshire" but as multiple sources and her own mother have claimed, she wasn't physically beautiful. Historians base their opinion on her portraits, which just show how biased I am because I see a physically beautiful woman looking back. But the portraits could also be inaccurate because Georgiana was a very difficult person for artists to paint for some reason. Gainsborough was said to have thrown down his paintbrush in frustration because he couldn't properly capture her countenance, and even her son. Hart, would go on to say no painting ever really looked like her. Similarly, when Fanny Burney finally met Georgiana she was surprised how average the looks of "the beautiful duchess" were. But upon further meetings she changed her mind and decided Georgiana was indeed beautiful.
One thing everyone did state about Georgiana is that she was very charming and difficult to dislike. She was also said to have a smile that could light up a room. Many historians have claimed that it was because of Georgiana's personality that she was dubbed "the beautiful duchess." Fanny Burney was determined not to like Georgiana when they met, but was won over when she discovered her to be intelligent and sincere. It appears that Georgiana's beauty was of a radiating variety, it was so incandescent that you could see it on her in person, but couldn't capture it in art. Georgiana is one of the few "beauties" in history whose title was based mostly on personality with a small influence from physical looks.