This one is. That's Saint Bernadette of Lourdes.
She was exhumed twice - once in 1909 and again in 1925. After the second exhumation the body was placed in a sealed glass coffin for display to the faithful. The first exhumation was made thirty years after her death. She had been placed in a sealed tomb (not buried in a wooden coffin in earth) and her body had been surrounded with moisture-absorbing charcoal and sawdust. I think anyone can begin to see how no "miracles" needed to be involved in the preservation of a corpse in those conditions. The report of the doctors who examined the corpse in 1909 describe nothing miraculous, just plain old mummification due to burial in anaerobic conditions:
"When the habits had been removed and the veil lifted from the head, the whole of the shriveled body could be seen, rigid and taut in every limb. It was found that the hair, which had been cut short, was stuck to the head and still attached to the skull, that the ears were in a state of perfect preservation, that the left side of the body was slightly higher than the right from the hip up. The stomach had caved in and was taut like the rest of the body. It sounded like cardboard when struck. The left knee was not as large as the right. The ribs protruded as did the muscles in the limbs."
(Drs Ch. David, A. Jourdan, September 22, 1909)
The second exhumation was witnessed by two other doctors, Doctor Talon and Doctor Comte, whose report read:
"The body is practically mummified, covered with patches of mildew and quite a notable layer of salts, which appear to be calcium salts. The skeleton is complete, and it was possible to carry the body to a table without any trouble. The skin has disappeared in some places, but it is still present on most parts of the body. Some of the veins are still visible."
So what about the perfectly preserved face and hands seen by thousands of pilgrims? They don't look like a mummy's face and hands.
Well, that's because they're made of wax.
One account says that the face and hands were simply coated with wax:
A worker in wax who had frequently applied such a coating to the faces of the newly dead was entrusted with the task of coating the face of the Saint who had been dead forty years.
(Frances Parkinson Keyes,
The Sublime Shepherdess, The Life of Saint Bernadette of Lourdes, 1940)
But others say a wax mould was taken from the face and hands and wax:
At this point, a precise imprint of the face was molded so that the firm of Pierre Imans in Paris could make a light wax mask based on the imprints and on some genuine photos. This was common practice for relics in France, as it was feared that although the body was mummified, the blackish tinge to the face and the sunken eyes and nose would make an unpleasant impression on the public. Imprints of the hands were also taken for the presentation of the body.
So what we have here is no "miracle". Bernadette Soubirous was buried in conditions that led to mummification and what pilgrims are shown is a mummy wearing a wax mask with wax hands. If they didn't, they'd probably be looking at a shrunken mummy's face - a bit like that of Saint Catherine of Sienna.