I've read a short story by F. Scott Fitzgerald called Afternoon of an Author.
There is a phrase I don't understand at all:
He passed a sporting goods store and looked in the window unmoved except by a first baseman's glove which was already dark in the pocket.
What does "dark in the pocket" mean in this context? By searching I only learned that "pocket" is the part of the baseball glove, but the phrase still doesn't make any sense to me.