Jim Cordy brought up the topic of shell grading, so i just thought i'd
review it again - what the heck??

Below is the scale as it is usually applied.  That said, it is a very
subjective activity:  some poeple like to call things "gem" that are not
in fact perfect (i get a real chuckle when i look at a list and see 80%
of the shells "gem"), and almost everyone tends to overgrade at one time
or another - "caveat emptor": check everything yourself.   There was a
movement a few years back to create a new category of "super gem", for a
gem shell with its original operc, and some people think that the
concept "gem for the species" is a valid one for species that almost
never occur in a true gem state.  For me, F+ is a nice, collectable
shell, but i am not a "gem maniac" :-=}.  Generarally if you want
everything perfect you should have lots of loot or lots of time and patience.

Gem:  completely perfect to the naked eye - no scars, pits, dull places
on shiny shells, etc.  There is a bit of leeway on growth lines (places
where the growth of the shell has stopped for a while then resumed, for
reasons of disease, lack of food, temperature extremes, etc.): most
people would agree that one or two very  thin growth lines do not change
the grade of shells like cones or volutes.

Gem-/F+++:  These grades are exchangeable.  I prefer Gem- myself, but
you can't fault someone for using F+++.  This is a shell so close to
perfect that you really have to look CLOSELY in order to see the imperfection.

F++: VERY high quality: extremely tiny flaw(s): This is a primo shell!!!

F+ high or F+/F++:  better than F+ but not quite up to F++ standards.

F+:  This is the true grade (in my opinion) of most shells sold or
collected: it is a good quality shell with a couple of small
imperfections that do not really detract from the attactiveness of the
specimen - say a small chip or two from the lip, a couple of moderate or
several smaller growth lines, a natural repair mark or two that doen't
mar the shell for most folk's appreciation, etc.

F/F+:  Almost F+, but getting a bit dicy:  ok for rare species or forms
or very interesting shells that one might not get another chance to get
soon, or perhaps just not at the price or trade value offered.

F: A shell that has a number of minor to moderate problems, or one big
one (such as a nasty scar or a broken lip or a number of heavy growth
scars:  for F shells the attractiveness is affected. Good for scientific
purposes, however, or for "place holders" of a species or form, or for a
really unusual shell.

Good: Not good.   Nasty stuff happening.

Fair: Not fair at all!!!  Recognizeable as the species or form but
beyond that.....

Poor: Recognizeable as a shell.

A dead-collected shell can be any grade at all - even Gem if the animal
died or was murdered minutes before the shell was nabbed!!  I think
there is a bit of discrimination going on regarding very high-end dead
collected shells: you have to price them quite low before they sell at all.

Protoconchs are important: it is questionable to call a specimen without
one F++, although if only the terminal whorl or so is gone and the rest
of the shell is in fact perfect, it's not so much of a crime.

The prescence of periostracum or an operculum is noteable - of course in
many species if the perio is still clothing the specimen, the true grade
is impossible to determine since the surface of the shell is obscured.
On the other hand, a land snail without perio is nearly useless, since
this is where much of the patterning and pigmentation is present for
these guys.

A shell that has been altered (lip filing is the most common form of
"alteration") in any way, or repaired, cannot really be graded since it
is not in its natural state.   Despite the fact that 99% of
conchologists have nothing to do with altered shells, the practice is
becoming more common than ever, and in the case of some of the new
coatings can be VERY sophisticated.  That's a topic for another time -
it would be a GREAT idea if someone would write a "definitive" little
pamphlet about the myriad ways shells can be "artificially aesthetically
enhanced" - and how to spot them without using rocket science!!

That's my 2 cent's worth on grading: hope it's of some value to someone!

From the middle of nowhere (but what's wrong with that??),
Ross.