www.cowries.info

[eclipsebay79]

Is there some literature which details color change and fading in different species of cowries? Some years ago I had the opportunity to collect shells on Diego Garcia. The isabellas I collected all had a beautiful charcoal gray dorsum when harvested, yet it faded in a matter of weeks to the tan color by which most of these shells are known. The light overglaze on the lynx I found became more opaque over many months. Yet other species changed almost imperceptibly or not at all. I would be curious to learn if the changes which take place in cowries over time have been documented and gathered together in one place. I also would be interested in hearing the experiences of other collectors.

[EmberCowrie]

well, from waht I've heard the fading varies from species to species and even from individual; to individual. C. Poraria is infamous for how much and how rapidly it fades; a shell that looked absoutely black when you collected it can wind up becoming pale tan in a month or two (I actually recently bought a gloriously colored poraria scarabeus; I'm actually keeping it in a dark box most of the time to try and slow the fading down as much as possible. Helvola's supposed to be pretty bad too. Oddly in both cases one of the "distingushing marks" of the Hawaiian subspecies (C. helvola hawaiinensis and C. poraria sacrabeus) is that they supposedly fade a lot less readily than thier fellow species members (at least that is what I've heard)

[Sleepycat]

I don't know how much results differ for live and dead collected specimens but my experience with dead-collected specimens is that unusually dark specimens of some species are more prone to fade than pale ones, and that carneola, erosa, also sometimes vitellus are especially bad in that regard.

Fading in once-nice looking carneola can be so bad in my experience that I would like to go somewhere where they occur every few years for replacements (and then throw out all the old ones!)

Notocypraea fade a bit, but not too bad. Have a small live-collected angustata from 25 years ago that has faded from dark purple through to a sort of medium purplish brown.

Kevin.

[RBS5]

I would be interested in additional information on this topic as well. I have heard, as well as experienced, considerable fading or purples (tips of hirasei and mikeharti especially) and reds (helvola)in several species. I have not purchased certain specimens simple because I know that as great as they look now fresh collected, in all to short of a time they will all settle out to a bland brown shadow of their former technicolor glory.
I've tried to photograph my more colorful selections so that at least I can have the images for posterity.

Rex

[XEP-BAM]

Colour fading is considerable especially for deep water species, for example U. petilirostris (from 200-400m) due to temperature difference in deep waters and surface. So, some collectors keep such shells in fridges.
Regards,
Sergey

[ozcyp]

Cypraea aurantiums usually display a purplish base when first collected and some mappa and hirasei have the purple canals also. After a few months the bases of the aurantiums turn to solid white and the canals on my mappa have almost faded completely. I know a collector friend who aquired fresh aurantiums and he kept them in his fridge. It slowed the fading process down, but eventually the inevitable happens, they all faded to white.
Sulcidentata, semiplota, xanthadon, erosa all fade considerably after a few months. I kept my best xanthadon in a fridge, but after 3 years they look no different to my others which weren't refrigerated.
On a different note, I collected large lambis lambis which have vivid, striking purple apetures but alas, they all fade to a greyish colour also.
It seems purple is one of the hardest colours to keep amongst shells.

[Trimaran]

I keep many shells in a refridgerator to maintain their fresh and rich colours (Now one whole fridge for the 'favourites' collection!). The colours in shells are mostly organic pigments that will degrade faster in brighter light and higher temperatures. The refridgerator works particularly well for purples, reds and black. Keep the shells in a ziplock bag and in a padded container and make sure they don't get too dry or get wet.

The fridge does not work forever but in my opinion makes the fresh dark colours last many many times longer. I have Lambis lambis from ten years ago that still have purple lips and red aperture and it is exceptional for storing volutes and Umbilia. Some colours such as the pink base of the large local deepwater Cypraea vittellus will still fade in a few months, but more slowly in the fridge.
Best regards from Queensland Australia

[Notocypraea]

Purple is the worst colour for fading from my experience.

unfortunately my favourite group Notocypraea all seem to fade somewhat esp dark angustata and the spectacular (when fresh) purple/ purple based comptonii.

[PVDB]

Putting LIVING animals in a %formol solution fixes the proteins and with correct total drying - out of sunlight - and without warming the animal soft parts become hard as stone. Colours are saved in some important way. It works well with sea creatures that have an exosceleton as(small) living corals, starfish and sea urchins. It works with molluscs too, but in cypraea the disadvantages are bigger than advantages. Formaline processed animals/shells must be conserved in a100% dry environment, any moisture will start the process of decay and attract micro-organisms.Some acid production will make more harm in the end, not only making the colour fade too but destroying gloss and eventually more of the shell.
Moreover formaline is dangerous and should be kept away from the eyes and absolutely out of reach of children and non responsible adults.

There MUST be technical fixation possibilities to conserve pigment. Algination?

Kind regards from PVDB , lets work on this topic!

[Bart]

Another species that has a bad reputation: Cypraea hungerfordi Sowerby.
Fresh collected specimens can be almost red in colour.
I have some older specimens (from Taiwan) in my collection. Though kept in drawers, the colour has faded to a kind of light yellow...