french version

History, description and identification of seashells - my collection from Madagascar

Anthozoa, Cephalopoda, Echinozoa
The best things I have collected in my life are my shells. They gave me the pleasure of their prodigious structure, the lunar purity of their mysterious porcelain.
Pablo Neruda (1904-1973)
It is perhaps a more fortunate destiny to have a taste for collecting shells than to be born a millionaire.
Robert Louis Stevenson (1850-1894)

1 - The most famous shell collectors

Seashell collecting is not a shameful disease, rather a virus that has infected many celebrities :

  • Scipio the African, Roman general
  • Louis XIII, King of France
  • Catherine the Great, Empress of Russia
  • Abraham Lincoln, 16th President of the United States
  • Edgar Allan Poe, poet “architect” of the modern short story
  • Albert the first, Prince of Monaco
  • Robert Louis Stevenson, Scot travel writer
  • Hirohito, Emperor of Japan
  • Pablo Neruda, Chilean poet-diplomat
  • Ian Fleming, creator of James Bond
  • Fidel Castro,the Cuban revolutionary and politician (anecdote regarding CIA)

2 - The origin of the shells

Seashells are one of the oldest forms of animal life.

Main milestones in animal evolution since the "big-bang of life" on Earth.
life evolution

(1-5)The five mass extinctions since the "big-bang of life" (540 million years ago aka Cambrian(*) geological era).
(*) Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Holocene(**).

(**)We are currently living in the Holocene era which began in 9700 BC. The Anthropocene period (or Human era), which began in 1610 when the Old World met the New World, was recently added. The impact of human activity on the climate, ecosystems and the overexploitation of natural resources has triggered what scientists suspect as the sixth mass extinction of our planet ☹ .

3 - Seashells and civilization

Human interest in seashells dates back to prehistoric times and had a strong spiritual symbology. Collections of shells have been found in the ruins of Pompeii, in Mayan temples in Yucatán and in caves in Burgundy (d'Arcy-sur-Cure) dating from the Neanderthal.

Seafood is often part of our festive meals but their flesh was an important part of the daily diet of prehistoric men living near the seashore. The shells have also proved to be very useful, in particular as a means of barter, in the making of tools and jewelry as well as in the production of dyes. They probably inspired human constructions and mathematicians and even poems.

Seahells are still a surprising source of lessons in the fields of archeology, medicine and biomimicry.

3.1 - Spirituality

In the Apache tribes, the "Sunrise ceremony" celebrates the coming-of-age of young Apache girls who wear for the occasion a piece of abalone shell above their foreheads. It re-enacts the legend of White Painted Woman who survived the Great Flood in an abalone shell.

The scallop shell ("coquille Saint-Jacques" in french) owes its french name to the eponymous St. James, who made the pilgrimage to Santiago de Compostela. Likewise, the elongated clam ("bénitier" in french) owes its french name to the verb "bénir" (to bless). This shell was often used as a holy water stoup at the entry of the churches.

In the ancient Hindu civilizations some newts were sacred, used as a trumpet, they eliminated negative energies and represented the sound of "Dharma", the teaching of the Buddha.

According to Inca legend, the power of Atahualpa the son of the Sun God, came from the shells of oysters of the genus Spondylus.

In Nigeria, porcelains represented a god's eye, the goddesses' uterus and the vessel of life and regeneration.

The Pompeian Romans and, later, West African women wore porcelain necklaces to prevent sterility.

The refined aesthetics of "sea of shells" site presenting magnificent photos, annotated with very beautiful texts, illustrates wonderfully the sacred respect of primitive peoples for the sea and seashells in particular.

holy water stoup (Saint-Sulpice church, Paris)

holy water stoup (Saint-Sulpice church, Paris)

scallop (Saint-Pierre collegiate church, French Riviera, France)

scallop (Saint-Pierre collegiate church, French Riviera)

3.2 Diet

The oldest consumption of shellfish by Homo sapiens dates back to around 160,000 years ago and they were an important source of food for coastal populations.

Marine pollution encourages us to be vigilant about the origin of seafood. In fact, most seashells are filter feeders which excrete part of the non-degradable toxins in their waste and in their shells. Four types of contaminants accumulate in shellfish

  • chemical residues
  • possible radionuclides
  • microbiological pollution (treatment plants, spreading of liquid manure and agricultural manure)
  • toxic substances produced by microalgae, which can cause severe poisoning

NB mussels and oysters detoxify from lead by storing it in their shells.

It will be noted that it is mainly bivalves that are consumed although half as numerous as gastropods :

  • oysters : rich in quality protein, abundant in vitamins and minerals, low in calories
  • mussels : rich in vitamins (B8, B12 and E), minerals (calcium, magnesium, iron, zinc, selenium)
  • cockles : rich in phosphorus, iron and zinc, combat fatigue and strengthen intellectual, physical and immune defenses
  • clams : it is one of the most energetic shellfish, rich in iron and vitamins B12
The oyster Lunch : Jean-François TROY(1679-1752)

The oyster Lunch
Jean-François TROY(1679-1752)

3.3 - Barter

With the sedentarization of prehistoric men, at the beginning of the Neolithic, the first forms of society appeared and the only way to acquire a good (tools, animals, food, ...) was to exchange it for a service or another item (barter principle).

But barter limits the development of trade because supply does not necessarily correspond exactly to demand and perishable goods are only available at certain times of the year (harvests for food for example).

Thus the emergence of exchange units : seashells in the beginning then precious metals (silver, gold).

The shells had the advantage of bringing together the main characteristics of a currency :

  • easily transportable and exchangeable
  • relatively difficult to acquire (no "monetary printing presses" effect)
  • the complexity of their forms protect them from counterfeiting
  • they can be stored for a very long time without deteriorating

It is especially the porcelains, in particular the two species below, which were used as money and which are more generally called cowries.

They are found at the museum of the "national bank of Belgium" and on the pediment of the building of the "Central Bank of the States of West Africa" in Bamako, Mali.

Moreover, from January 1, 2022, the new regional currency of West Africa will be called the "cauri" replacing the CFA franc.

Monetaria moneta

Monetaria moneta

Monetaria annulus

Monetaria annulus

3.4 - Tooling

The shells were used to make various tools (scrapers, projectile's points, vase, hook, etc.).

In the Marquesas Islands, some varieties of murex or cowries were cleverly modified to serve as peelers for the breadfruit.

In classical times, in Athens, citizens who endangered democracy (because of their power) were banished for ten years. The vote for the judgment was written on oyster shells, hence the term ostracism (from the Greek ostrakon, oyster).

conch primitive horn

conch primitive horn

sharply carved columella

sharply carved columella

3.5 - Jewelry and decoration

Not to mention pearl oysters, this is the area that best contributes to the popularity of seashells.

Mother-of-pearl (the inner layer of the shell) was an element of choice in jewelry and marquetry.

Urfé cave(haliotid frieze)

haliotid frieze

Urfé cave (Beard of pelican's foot)

Beard of pelican's foot

The natural beauty of seashells has often been used in decoration. These images come from the rockery cave of the Urfé castle

Cameos, these small, slightly raised engravings were cut from agate. The beginning of travels around the world, in the XVIIth century, allowed the discovery of new shells which present a natural gradient in the thickness of the shell.

cowry necklace

cowry necklace


cameo (Cassis madagascariensis)

3.6 - Dyeing

In ancient times, the color purple, the prerogative of the Roman emperors, was much sought after. The oldest traces have been found in Crete and date back to 1600 BC.

These dyes come in particular from "Bolinus brandaris" or "Stramonita haemastoma"

Bolinus brandaris

Bolinus brandaris

Thais haemastoma

Stramonita haemastoma

3.7 - Architecture

We can notice the influence of shells on the architecture of some traditional constructions

Tây Phuong pagoda

Tây Phuong pagoda

asian sea seashells

asian sea seashells

L'escalier de Chambord

The keep of the Château de Chambord has a staircase in its center made up of two superimposed helices and ends with a single helix staircase inspired by the columella of seashells.

Opéra de Sydney

The roof of the Sydney Opera House represents superimposed seashells.

Lunulicardia retusa auricula

Lunulicardia retusa auricula

3.8 - Mathematics

Some seashells conceal true mathematical objects :

Cymbiola innexa & Oliva porphyra

Cymbiola innexa & Oliva porphyra

Sierpinski fractal triangles

Sierpinski fractal triangles



logarithmic spiral

logarithmic spiral

3.9 - Archaeology

The analysis of shell's remains provides precious indications for the study of archaeological sites (archaeomalacology)

3.10 - Medicine

In medicine, the amazing properties of toxins from certain poisonous shells (Conidae) are being studied for analgesic treatments, epilepsies or the recovery of damaged nerves.

The "Conus magus" cone venom has made it possible to synthesize an analgesic for severe chronic pain, 2000 times more powerful than morphine with the advantage of not causing addiction.

The cone venom "Conus victoriae" allowed the synthesis of a drug used in the treatment of neuropathic pain 100 times more active than last generation antiepileptics.

Conus magus & Conus victoriae

The venom (µ-conotoxin) of certain Conidae (Conus marmoreus, geographus, striolatus, ...) contains peptides (which we do not know how to synthesize) which allow to close / open the sodium channels (propagation of the nervous signal) and therefore to study the functioning of the nervous system and to produce new insecticides, local analgesics, antiarrhythmics, anti-epileptics, etc.

3.11 - Biomimicry

Surprising properties have been discovered in molluscs, promising sources of technological innovation :

The shell of abalones (Haliotidae) are twice as hard as the best high-tech ceramics. The pearly coating is a perfect tiling which combines rigid layers of calcium carbonate (aragonite) and flexible layers of proteins (Lustrin-A) which gives it a flexibility capable of absorbing violent shocks and supporting weights of several tonnes. Scientists are inspired to design new materials that will be revolutions comparable to the advent of the Iron Age or the Industrial Revolution.


The byssus of mussels (Mytilidae) which allows them to attach to rocks is, in fact, the most powerful glue in the world: it resists UV, salt, high and low temperatures, it is very resistant and especially glue under water. These filaments also make it possible to produce the best suture threads used in particular in cosmetic surgery.


4 - Story of this site

4.1 - Genesis

I have inherited a collection of shells mainly from Diego-Suarez (Madagascar). It is not only composed of shells (gastropods and bivalves) but also of nautilus, sea urchin, argonauts, corals.

I was only 6 or 7 years old, and I remember the weekends on these vast deserted beaches of Diego-Suarez where, with my father, we spent hours collecting shells and corals. Over time, my parents built up a remarkable collection which they brought back from Madagascar. Shortly before their death, the house had to be sold and for lack of space, all the shells were quickly packed and piled up in a basement for years while they were the pride of my parents.

Now retired, I have decided to give them a second life. For this, Internet seems to me the best way to expose them to potential amateurs. So I gradually brought out the shells from the basement to photograph and measure them, then I repacked them and put them back in the basement (hopeful of finding a definitive place). As we open our Christmas presents, I opened, week after week, many suitcases filled with seashells!

Before creating the site it required a hard work to produce its content :

  • photograph (front, back and possibly in profile) each specimen of several hundred species
  • crop each photo on a transparent background and fusion of the different views into a single image
  • Identify hundreds of species took me a long time burning the midnight oil and it is quite possible that some are still wrong, I humbly accept your enlightened remarks. I had no certainty about their origins (some shells were collected on the spot but, others bought from local merchants). One can however reasonably assume that they come mainly from the East African coasts or the Indian Ocean.
  • for each family, write a description sheet (common names, common appearance of the shells, food, living environment)

This is how I got a taste for the world of seashells and I now understand better why they have fascinated so many people for so long. To my surprise, I discovered on the beaches of the French Riviera, many shells from different families (Bullidae, Cerithidae, Columbellidae, Conidae, Cypraeidae, Haliotidae, Pisanidae, Trochidae, Triviidae , Vermetidae, Arcidae, Limidae, ...) which enriched my collection!

Drawing on the experience of my research, I wrote a mini-guide for identification of shells which :

  • lists some websites that have been of great help to me
  • for each seashell family, its classification (Family ← Super-family ← Order)
  • indicates some observation keys on certain details of the shells

However, to be able to identify a shell you need to know a certain number of specific terms and a minimum knowledge of the anatomy and structure of a shell. So, I made a compilation of information available on the web : shells for dummies

4.2 - Creation of this site

At the beginning, I wrote a small utility (a bash script) to make my job easier and to update the site automatically as much as possible after each modification :

I used three powerful free softwares :

  • "ImageMagick" for pictures batch processing
  • "LibreOffice Draw" for the diagrams
  • "Gimp" for image editing

Time passing, I added features and improved ergonomics. This program can now create websites from various "collections".

The success of free software is due to the sharing of "source code".
In this spirit, this site provides the application that allows you to create sites on this model.

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