Fluorescence is a difficult topic, means how the diamond changes the color under UV light. eG. a with diamond (river D-E) can change to blue or very bad to yellow or green. If you choose one in a bit colored (wesselton G or less), it can have a positive effect, than it appears often more white. Normally for bigger diamonds from H-D color I would choose “none” or “less” fluo. And in each case choose a diamond not less than very good cut. In my opinion it’s more important than the size. So it’s not a inclusion not one of the 4C’s but important

Hope it was not confusing, but in the internet you will find lots of pictured information about this.