Gersemi in Old Norse derives from "treasure" or "riches". She is mentioned in passing to all things that are precious. Gersemi and her sister are commonly found in primary texts together structurally [mentioned together] and also around each other, independent from other divinities in lore/mythos. Gersemi is regarded as a goddess of beauty and of personal adoration & possessions.
Gersemi is not as well-attested, as far as Snorri-Edda or the Íslendingasögur (without reference to mythology Hnoss). In Chapter 10 of the Heimskringla, Ynglinga saga, Snorri Struluson refers to to both Hnoss and Gersemi-- in an euhemerized account:
"Her daughters were called Hnoss and Gersemi. They were very brautiful. The most precious treasures called by their names."
Correspondingly, her physiological and physical characteristics when presented are nearly identical to her sister's-- however she has golden blonde hair and bluer eyes. Hair that could resemble gilded treasure, an epitome of her name and embodiment. Unlike her sister, Gersemi is assessed to be slightly more rambunctious and conceded from their raving attention in facet to allure.