They may not be precious stones but they are like hidden treasure for those who come across them.

Messages of comfort, detailed paintings and colourful outlines of cartoon characters have been spotted in the most unexpected places.

Either kept for safekeeping or rehidden for others to enjoy, these simple rocks have spread across the UK as a way to make people smile when they least expect it.

Love on the Rocks is a semi-secret project where people of all ages join in together to post pictures of rocks they've painted, hidden or found on Facebook.

As the rocks are discovered in their hiding places, the movement grows by word of mouth as more and more people decide to join in the fun.

It is thought the phenomenon was inspired by The Kindness Rocks Project which began in the US.

Founder Meghan Murphy found comfort in finding pieces of sea glass and heart shaped rocks on the beach following the death of her parents.

Finding joy in unexpected places, one day she wrote a message on a rock and left it on the beach only for her friend to find it.

Whilst denying she had created the little piece of art, she was told that the message had brightened her friend's day.

From there, the project snowballed, with rocks painted in bright colours, etched with designs and covered with positive and uplifting messages hidden in safe spaces to be found by complete strangers.

The idea has expanded into Love on the Rocks with Facebook pages popping up across the US and the UK dedicated to those who enjoy creating, hiding and finding little treasures.

"I know it makes me smile when I find somebody else's painted rock, so I like to think when somebody finds one of mine it brings a smile to their day," explains Nicky Hamilton from Ayr.

"It's nice if you see a photo of the rock being found, but it's fine if you never know where they went, a little bit of you is making somebody's day."

Recently hiding some of her own rocks in Florida on her travels, Nicky's decoupage designs are a hit with members on the Love on the Rocks Scotland Facebook page.

Started by Andrew McVie, the 24 year old launched the Scottish group after being inspired by others sharing their designs on the social media site.

"The main group for the UK was mainly just people from outside Scotland posting so I decided to set up a page for Scottish people to use and engage with," he says.

"Love on the Rocks is a way to explore the community and see different places."

Stace Reid, a member of the Love on the Rocks UK Facebook page which has more than 60,000 members, explains that the project has unearthed a hidden talent for painting.

"I got into this hobby because my four children watched for clues on the Kirkcudbright stones facebook page every Saturday to find stones hidden in Kirkcudbright by a couple of the locals," she explains.

"I felt it would be good to return the favour and paint and hide some and quickly became addicted.

"I didn't realise I could paint at all," Stace adds.

"I'm really enjoying painting them now it is a fab past time and I am enjoying the exciting designs I can do with it."

It's a hobby open to all, with Love on the Rocks pages encouraging creativity while also reassuring participants that artistic talent isn't a necessity, just the drive to do something that will make a stranger smile.

Rocks should be easy to come by, in ploughed fields or in woodland areas it is often suggested, but people are advised not to take pebbles from the beach.

Even if you can't find any near you, craft stores and garden centres are perfect places for those looking for blank canvases.

Children and adults alike revel in the joy of finding the hidden treasures, from zoos to parks and woodland areas to the waterside.

Ceri Nicoll from Leslie, Fife says that going 'rocking' with children Jayden and Carli has been a great way for the family to go exploring.

"We have collected about eight rocks from Riverside park in Glenrothes and a few from various places in Kirkcaldy," she says.

"It's been a fab way of getting the family together and getting outdoors."