The 11-year-old was at Loch Insh Outdoor Centre near the village of Kincraig close to Aviemore when she fell ill.
Ruby, a primary seven pupil at Whiteabbey Primary School, was found unconscious at around 2.30am on Wednesday.
Emergency services were called and despite efforts to resuscitate her, she was pronounced dead at a nearby hospital.
On Thursday, her family described the little girl as "our precious Ruby".
"We are obviously devastated at the loss of our precious Ruby. Due to the distance involved and due process required, funeral arrangements have yet to be confirmed.
They added: "The family would ask that their privacy be respected at this terrible time."
Ruby was one of 58 children and six teachers on the trip to the outdoor activity centre, and Whiteabbey principal Peter Wright said they were saddened by her death.
He said: "She really did bring a brightness to every day in the school and clearly at this time our thoughts are with her parents, brother and wider family."
The trip was cut short and the pupils returned to Northern Ireland on Wednesday night, just hours after the little girl died.
Pupils were greeted by their parents and counsellors, who offered support to the children.
Police in Scotland described Ruby's death as unexplained. A post mortem examination was due to be carried out on Thursday.