Reviews and Commentaries120 Scientific American November 1997

Several years ago I became curi-

ous about a 17th-century Per-

sian astrolabe maker called Abd

al A’imma the Younger. My trail of re-

search eventually led to the Boston Mu-

seum of Fine Arts, which had a brass

instrument supposedly inscribed by

him. The metalworking and calligraphy

were fine enough, but it quickly became

apparent to me that the astrolabe never

could have functioned as an astronomi-

cal instrument. In a word, it was a fake.

The curator’s response took me by

surprise: “This will make a good display

for us. The museum is planning an ex-

hibition on forgeries. We have two as-

trolabes that look very much the same

to the untutored eye, but one is genuine,

the other fake. The comparison will help

teach what is essential on an astrolabe

and what is ornamental nonsense.”

Unfortunately, the exhibition never

came to be. The Boston trustees vetoed

the idea because they didn’t want to ad-

mit how often the museum had been

caught out collecting forgeries. Yet lat-

er, in 1990, the British Museum staged

a stunningly successful show of fakes—

ranging from a medieval chastity belt to

the infamous jaw of Piltdown Man.

These artifacts, testimonials to deceit

and gullibility, all raise the sensitivity of

our perceptions. They teach us to see

more critically as we (and fallible ex-

perts) gain greater insight into the often

blurred line between the authentic and

the counterfeit.

Yale’s Vinland map, the Getty’s bronze

horse, Rembrandt’s Man in a GoldenHelmet—all of these challenged objects

have attracted greater scrutiny and

study than they ever would have had as

complacently accepted antiques.

Recently my wife, Miriam, and I had

our vision sharpened in an unanticipat-

ed arena. Ever since we had a glorious

opportunity to sail in Melanesia during

the 1986 appearance of Halley’s comet,

we have been intrigued by the astonish-

ing variety and beauty of seashells.

Over the years we have amassed a siz-

able collection of cowries, cones and

conches. The invention of scuba diving—

and the knowledge by fisherman that

shells are eminently collectible—sub-

stantially democratized some once clas-

sic rarities. An example is the elegant

Lister’s conch, which fetched $1,000 at

auction in 1970 but today is available

for a few dollars. And the “matchless”

cone Conus cedonulli, which brought

six times the price of a Vermeer paint-

ing at a 1796 auction, can now be pur-

chased for about $100. Still, many spec-

tacular gastropods outstrip our modest

budget.

We were therefore quite surprised to

discover in a small shop several exquis-

ite shells at bargain prices. Puzzled, I in-

quired about them. “We got them inex-

pensively from the fisherman, so they

are good buys,” the dealer explained.

Blissfully forgetting the adage that

where money is to be made, forgeries

abound, I succumbed to temptation,

buying two beautiful cowries—a valen-tia and a smaller sakurai, the latter a

shell at the top of the rarity scale. When

I got back to my reference books, I

found that the sakurai cowrie was a

twin of the one illustrated in The Shellsof the Philippines. That should have

triggered an alarm, but it didn’t.

Icould not help gloating over our ac-

quisitions, so I mentioned them via e-

mail to Guido Poppe, one of the lead-

ing collector-dealers in Europe. Poppe

promptly congratulated us on our bonnechance, then dropped his bombshell: “I

hope you didn’t buy painted specimens.”

Shaken, we consulted A Guide toWorldwide Cowries to see if there were

any similar but cheaper species that

could be repainted into a rarity. This

was an educational experience in itself,

taking a close look at the shapes rather

than the color patterns of the cowries:

the bottom line was that both species

had unique shapes.

Placing the specimens under magnifi-

cation—10 to 30 power—revealed a

wealth of detail, but it still left their sta-

tus ambiguous. The single-colored sa-kurai pattern looked suspiciously like

delicate penmanship. To get an expert

opinion, I sent the shell to Gary Rosen-

berg of the Academy of Natural Scien-

COMMENTARY

WONDERSby Owen Gingerich

In Praise of Fakes

“If it’s a fake,” Miriam declared, “it’s worth the

price as a piece of fine art.”

DU

SAN

PET

RIC

IC

Copyright 1997 Scientific American, Inc.

ces in Philadelphia. Although the acad-

emy’s shell collection contains 12 mil-

lion specimens, the sakurai is so rare

that it is not represented in their hold-

ings. Nevertheless, Dr. Rosenberg could

give a definitive verdict.

“When I opened the box,” he report-

ed, “I thought, ‘What a gorgeous shell!’

But under the microscope, I saw that all

the color lay sharply in the same plane.

On a genuine pattern, the animal de-

posits the pigments all through the out-

er layer, producing a somewhat fuzzy

appearance. Furthermore, the surface of

your shell is too uniform, so a reflected

light stays steady as the shell is rotated.

On an unretouched shell, the growth

lamellae give a jerky effect. Your shell is

a genuine sakurai, but its splendid pat-

tern is a forgery.”

The fraudulent sakurai cast doubt on

the larger valentia. The valentia’s pat-

tern, however, was far more complex,

with multiple layers and a palette of

subtle colors. “If it’s a fake,” Miriam

declared, “it’s worth the price as a piece

of fine art.” An art historian made the

next suggestion: “Take it to the physical

conservation laboratory at the Fogg Art

Museum. They can use infrared to see

if anything has been repainted.”

The conservators chuckled at that ad-

vice. Infrared is useful in some situa-

tions to detect overpainting on canvases

but not appropriate here. In any case,

the museum’s experts gave the valentiaa hard look under their microscope:

“There are no signs of brushstrokes or

edge bleeding that we would expect

with painting on porcelain, for exam-

ple. If this is a fake, it’s a much better

job than we can do in the lab.” Still,

they agreed that one minor blemish on

the surface looked like a fingerprint in

lacquer. Determined to get a definitive

answer, I gave permission to dissolve

the finish in some inconspicuous spot.

When I returned the next day, they

were wreathed in smiles. “We’ve tried

every solvent in the cabinet,” they said.

“Nothing touches it. Your shell has a

natural surface, and that ‘fingerprint’

has got to be a natural defect.”

As a final clincher, they suggested

putting the shell under ultraviolet light.

I knew the result already. Most shells,

including the valentia and 180 other

species of cowries that I have tested,

have no ultraviolet features. The two

exceptions are the venusta cowrie from

southwest Australia and the relatively

common mappa, found throughout al-

most the entire Indo-Pacific. Both spe-

cies fluoresce with a magnificent orange.

My discovery is well known to mala-

cologists, although I’m not sure they

know why these species glow that way.

In terms of sharpened perspectives,

the money for the “enhanced” specimen

was well spent. The happy ending of

my story is that the dealer who sold the

shells was as surprised as I when one

turned out to be fraudulent, and she im-

mediately exchanged the sakurai for a

real one (which was not so easy, consid-

ering its rarity). And then she sold me

the fake at a reduced price.

OWEN GINGERICH, professor ofastronomy and history of science at theHarvard-Smithsonian Center for Astro-physics, has a “collecting gene” thatgives him a passionate interest in rarebooks and elegant shells.

SA

Copyright 1997 Scientific American, Inc.