Grading Shells & Shell Dealers
On Grading Shells:
In practice, most dealers from time to time exaggerate the quality of their shells - this is human nature: the trick is to learn which of the dealers you propose to deal with do this habitually (no fingers pointed, but if a list comes your way with 90% of the shells rated GEM, this is highly suspicious!!), and which do it simply by accident or irregularly.
In my experience, "GEM" shells, except for a few species of cowries and a few cones that like to live in low-energy environments, are RARE - you can almost always find something "wrong" ( a subjective concept: for some, thin growth lines don't count unless there are a lot of them, while others consider any tiny irregularity to be a "flaw", hence undesirable in a natural object) on any shell, even without a microscope. WITH a good 10x lens, it is easily seen that there is no such thing as a "flawless" shell.// F+ is the most commonly used grade, and is a rather subjective, "flexible" term in practice (nobody likes to outrightly call a shell "F" since it is the kiss of death for selling it unless you have a good low price on the thing!!): generally it means a good quality shell - minor repair or other irregularity or two, such as a couple of little lip chips or a small growth mark, which do not interfere signifigantly with the natural beauty of the shell - ie, they are easy to overlook unless one is quite particular. in general, if a shell is rated F, it is not that pretty, but is good as a study shell, or as a "starter" or "place-holder" for that species, while F+ specimens look good in most collections. F++ and Gem- are interchangeable, and mean "ALMOST" GEM - only the most particular of collectors would spurn a shell of this quality. F+++ or worse, is a meaningless designation, meaning F++/Gem-.
Of course, grading is subjective, except for "GEM" which SHOULD refer to a shell with NO visible imperfections or irregularities (if it does not, it is a mistake) - one person's F++ might be another's F+, and some dealers don't even use the F++/Gem- designation. Let the buyer be always on their guard!!
On Grading Shell Dealers:
Buying shells isn't like buying most "normal" retail goods, but involves a surprisingly large number of factors such as:
The best way is just to
I would add also,