The discovery has resulted in a gem rush, as eager treasure-hunters flocked to the remote area in the northwestern Boyaca region.
"I was working and I noticed something shining and I asked myself, 'What could that be?'" construction worker Julian Correa told local broadcaster RCN.
"I am not from this area, so I mentioned it to someone who's from here,and I was told it could be that there are emeralds here," he added.
Correa was part of a team drilling and repairing a steep mountain road with a 500m (1,600ft) drop down one side when one of the party came across the bright green stones.
Local resident Esteban Pena said that people had rushed to the area in the hope that they could cash in on the discovery.
"Some people found [deposits valued at] 5m pesos ($2,750, £1,700), [some even] 10m pesos ($5,500, £3,400)" he said.
Colombia produces approximately 60% of the world's emeralds, and the Boyaca region is one of the country's main mining centres.
Local police have now cordoned off the road in question in the interest of public safety.