She is wearing a sheer blouse and a deep-purple (mulberry-colored) shimmery gown. She also has pearl earrings and pearl-topped pins holding her tail in a bun. She styled her mane slightly differently to get a fancier swirl. , , , and Equestria Daily got us more into the idea of exploring these cool “Rare Mares”!
This is completely done with vectors, even the shading! Here is a look at what the various objects are that construct her: