Sarah Jane Adams packs a punch in her new memoir Life in a Box

And yet the 63-year-old, with a "good bull.... radar", baulks at the thought of being put in a box and labelled.

Since becoming an international model and overnight Instagram sensation in her 60s, Sarah Jane has graced the catwalk at Melbourne Fashion Week, is an ambassador for Priceline pharmacy and has provided plenty of fodder for fashion bloggers around the world.

But as she tells The Senior, it is her first love of antiques and jewellery design, which grew from her time scouring London markets, that is her real passion - a topic she delves into in her new "unorthodox biography" Life in a Box.

In it, Sarah Jane tells her story through a lifetime's collection of rare pieces and worthless objects, as well as personal photographs and effects from her "estate".

"Who I am is nothing to do with the perception of who I am," said Sarah Jane, who started the hashtag #mywrinklesaremystripes on Instagram.

Keen to avoid writing the cliched "how to be old and inspirational" style book, Sarah Jane wanted to pen a memoir through objects and memories. "I spent a year and a half putting my heart and soul on the line," she said.

The notion was inspired in part by the death of her father and having to deal with all his "stuff" and also witnessing families' "pain and confusion" selling off heirlooms when she was working at auction houses.

But when it came to the book's style, it was her publisher who gave her the clue. "She dug out a book about a broken love affair written as an auction catalogue. I burst into tears, and said 'This is it!'"

In a series of "Lots", Sarah Jane takes the reader through the catalogue of her life: from her English childhood to her first life-changing journey to India and onward to Australia; the sadness of never knowing her twin sister; her time on the 1970s London music scene; the birth of her daughters; and life as a single parent running an international antique jewellery business.

The title for the book Life in a Box came from the author's grandmother Nanny Win's own "life in a box".

"When I was little, we would secretly open it together and she would share her memories, her deepest thoughts, wishes, regrets and tales of her life and times," writes Sarah Jane Adams.

"It was this tin full of memories that gave me the title for this book and taught me to recognise, extract and condense the meaningful from the mundane.

"I'm actually terribly organised - you wouldn't think that by looking at me," she said on the process of going through her treasures.

"But as a jewellery dealer, I've had to categorise things in terms of style, genre and era, so my entire life is packed away in boxes."

Unpacking them all was a cathartic experience. "I've laid everything bare in the book," she said. "But ultimately, they're just things."

Of course, there's a tongue-in-cheek nod to "not fitting in" in the title too. As she writes: "In every aspect of my life I was a misfit. I still am," she said. "The book itself is about not fitting in - the title is a huge pun intended.

"I don't want to fit in - the 'norm' is a construct that, to me, is so hideous."

A favourite from her "cabinet of curiosities" is a collection of enamel butterflies.

"They're not the most valuable, but remind me of the days the three of us were in our cottage in Chichester. The brooches symbolise those hazy summer days in the English countryside, when red admirals would come fluttering past."

And like her much-loved metamorphosing butterflies, Sarah Jane is always evolving.

"I have no regrets," she said, of being thrown into the social media spotlight as an Instagram "icon".

"But I've got less life than I've had and I don't want to waste it sitting on Instagram writing inane comments on lipstick."

Instead, Sarah Jane is pressing the reset button on her jewellery business Saramai Jewels. "It's having a major reboot. Watch this space."