When it comes to gems there are rules and there are rules. For instance an unexciting straw yellow diamond with a lot of flaws is not pretty to look at. Its value will suffer when compared with a diamond identical in all ways except for our new entrant being white, white and clean, clean. Diamonds that are clean and white will always be considered valuable—that is a rule likely to always stand.
On the other hand in colored stones the rules are not always written in stone—so to speak. Sometimes there will be a consensus as to value but many colored stones that are not necessarily the top of the value chain may just be quite beautiful—simply not as pricey. A good source of these conundra are garnets, tourmaline and sapphire. What these three types of gems have in common is that all three come in a dazzling array of colors.
A good “for instance” is the pink sapphire in the photo. It is an amazingly beautiful stone but it is not considered top color pink but really who cares? It is beautiful, just not as pricey as a similar pink sapphire in a more intense color. The truth is that many ladies would like to wear this lighter, more subtle pink with their wardrobe than some of the more exotic fuchsia and higher priced pink sapphires. On the other hand why not own all the colors?