"The miraculous orb soared, shimmering with iridescent hues, across the awed faces of those gathered around." This is not okay if you are writing about a toddler with one of those bubble-blowing rings. It sounds stupid. An example of the very extreme of Purple Prose would be something like writing a book review and saying you were overzealous to finish the book and a wave of nostalgia swept you as you closed it... we're getting into Troper Tales now, though.