It was extracted from the throat of a young woman at Sydney Hospital in the 1920s – a timeless reminder to young people to listen to grandma's advice and not suck their hair.

It is not the giant hairball, but a decayed hand with missing fingers suspended in formaldehyde that stops the museum's curator, Elinor Wrobel, as she walks through the collection of morbid anatomy on Macquarie Street, Sydney.

She says James Young, the first X-ray technician employed at Sydney Hospital, was a "martyr" to the cause of science.

"He used to test whether the equipment was working by putting his arm under it before the patient was put in position. Progressively, his fingers were amputated while he was alive, and he had extensive skin grafts to try to control the advance of the cancer. His fingers were amputated and then, ultimately, both hands."

Young died of squamous cell carcinoma from overexposure to radiation, the same disease that also killed his boss, Dr Herschel Harris. "Even when evidence emerged on the harmful effects of radiation, he continued working, believing his experience would help others," Wrobel says.

She regards the hand "as the most precious historical object in the morbid anatomy collection".

At the Powerhouse Museum, Matthew Connell, curator computing and mathematics, has a range of offbeat favourites, ranging from the endless variations on typewriters to the trays of barbed wire, found in the museum's vast basement. A new favourite, recently donated to the museum, is NSW's first official inch – a thin piece of metal in a wooden box.

"It is a very sweet inch, with its tiny little markings on it," he said. It is divided into 10ths and 100ths. A metal measure, which sits in a timber box with its own magnifying glass, the object is "very accurately an inch in length," Mr Connell says. It was likely used in machining.

He says the word for inch comes from the Latin word for one 12th, which was the average width of a man's thumb as the base, and was used by builders. An inch also related to an actual hand, a measurement used for horses, and a width of a hand is the width of a common brick, and there are three hands in a brick, he says.

"I love standards. They're magnificent things." He says they are a hidden technology, necessary for our built environment and for science, and are rarely given the attention they deserve.

The inch came from the Office of Fair Trading, the department responsible for implementing standards.

Chris Reid, an entomologist at the Australian Museum, finds it difficult to choose between his favourite beetles, many named after his wife, Safrina.

"I have named about four or five species for my wife, but only the pretty ones."

He particularly likes a jewel-like beetle, called Spilopyra safrina, from the Carbine tablelands in northern Queensland.

The differences between the various species of beetles would not be obvious to the layperson, but Reid can identify distinguishing features.

"Spilopyra safrina has different shaped colour patches, is hairy underneath, and has red feelers.

"I've also named two other leaf beetles after my wife, using her nickname, Evi: Taumacera evi and Taumacera dekatevi.

Would his wife prefer flowers to beetles?

"I don't work on flowers, so she doesn't have that option. I could name dung beetles after her, but I don't think that would be appropriate," he says.

The diamond heist that wasn't

From details on fish sex to the story of Captain Cook's Cape, a new book from the Australian Museum, Feathers of the Gods, highlights 180 years of discoveries, thefts and ancient lives and cultures.

The book, at the museum shop, contains a powerful parable on the virtue of reading the labels on exhibits painstakingly acquired over the years.

Take the case of the thieves who heard about the museum's collection of sparkling diamonds, acquired in 1900 from the Mont de Piete Pawnbroking Co in Sydney.

The collection of 14 glass models, includes high-quality glass copies of the Koh-I-Noor – once the world's largest known diamond and one of the British Crown Jewels – and the Orloff diamond, given to Catherine the Great of Russia.

So convincingly did they look that a thief hid in the museum one evening in March 1968, smashed the display and according to Ross Pogson, the museum's collection manager of geoscience, fled with the diamond models.

Three months later, the diamond models were returned in a brown paper parcel from Canada

with a note, saying "Sorry gentleman [sic], they are not real."

So much for observing the most basic duty of a museum visitor: read the labels.