Ljósbjörg Petra María was born on Christmas Eve in 1922 in a small traditional farmhouse on the northern shore of Stöðvarfjörður, called Bæjarstaðir. The farmhouse, that was only a few square meters in area, does not exist any longer but its remains are still visible and serve as a reminder of the struggle for existence faced every day by those who lived in Iceland in such humble dwellings in a bygone era. Petra was the daughter of Sveinn Björgólfsson and Svanhvít Lára Sigríður Pétursdóttir; Bæjarstaðir was their home for fourteen years but they moved to the Kirkjuból village (now Stöðvarfjörður) in 1927.
Understandably Petra did not remember very much from her days in Bæjarstaðir and what little she could remember, were things she was sure were mixed with stories from her parents. One of those mixed memories was when her siblings took Petra up to the cliffs near their home. They sat her down on a ledge and went on playing nearby. After a little while, the fog suddenly crept in and covered the cliffs. Petra, her brother and sister, didn't see anything and they started crying and kept on crying for quite a while. But as always the fog surrendered after some time and the children were able to go back home. It is very appropriate that one of Petra's first memories was connected with nature and specifically with the cliffs where she later looked for and found her first stones.
The first clear memory that Petra had from her childhood was when the family moved from Bæjarstaðir to the village Kirkjuból (now Stöðvarfjörður). Petra didn't like the changes at all and even though she was only five years old she demonstrated her desire to turn back to her old home in her own unique way. She protested byclimbing to the roof of the storehouse that was next to their new home and sing, or curse depending on her mood and for how long she had been sitting on the roof.
Around the same time Petra and her family moved to the village she fell seriously ill. For a whole year she was so sick her parents had given up hope several times. But she pulled through and went from strength to strength in the following years, as the boys in the village found out when they were teasing Petra or her friends. In the following years Petra grew up to be a very tough, industrious and stubborn little girl but these characteristics aided her later in life when she came face to face with all kinds of adversities.
Beautiful stones were always a part of Petra's live. In the beginning she collected stones that she could use for drawing. Later she collected other kinds of stones that she used as decorations in little huts (called "gullabú" by locals) that she and her many friends, built all over the village. Some of the stones she used as vessels for all kinds of "food" that she offered her friend in little "tea-parties". The menu was "mud-pies", berries and an assortment of vegetables that Petra "borrowed" from vegetable patches all over the village. Some of these stones were the first mineral cavity fillings that she found, around the age of seven.