Some uncommon descriptive words include "sartorial," "evanescent," "diaphanous" and "lithe." Lists of uncommon descriptive words, especially those geared toward a certain category of description, often help writers find just the right word to describe something, as does a good thesaurus.
Compiled lists of descriptive words are especially helpful to jog creative energy. Some lists are compiled without regard to what the words describe, focusing instead on the beauty of the words themselves. Many old words have a compact meaning that is cumbersome to express in more common terms, such as "sartorial" in place of "related to clothing and tailors" or "evanescent" in place of "quickly fading from memory." Uncommon words such as "minatory," "querulous" and "arcadian" may describe a subject perfectly.
Other lists focus on words for particular subjects they describe. Words such as "exquisite," "alluring," "lustrous," "vintage," "hypnotic," "sparkling" and "flawless" are not synonyms, but they could all be used to describe jewelry of some sort. Lists like these are helpful for writers to expand their vocabulary related to a certain topic, enabling writers both to avoid repetition and to be more precise with their language, such as using the more specific "lithe" in the place of its more common synonym "graceful," or using the more descriptive "diaphanous" in place of the more common "delicate."
The most basic tool for finding a nearly unlimited number of descriptive words is a good thesaurus, which lists uncommon synonyms and antonyms for common words in dictionary format.