-- a cinquain
favorite color --
beautiful and dangerous like
* * *
A cinquain is a poem of 5 lines. Individual variations may or may not add additional parameters.
Glas is a quintessentially Celtic term that can mean blue, green, gray, or silver -- or any combination of those colors. It has mixed connotations of something beautiful but changeable and potentially perilous. This makes a lot more sense if you know that it actually means "sea-colored." Here's a discussion of the same word borrowed into Welsh. The closest English translation is "hazel."