This work presents "LeARn," a new network-based collaborative learning environment that employs augmented reality to transform a real-world surface into a virtual lab. To demonstrate the system, a scenario with a virtual chemistry lab is presented. In this demo, any real-world surface is augmented by virtual lab equipment utilized in a chemistry experiment. The virtual lab is hosted by the instructor, and all the students can join the lab only using their mobile phones or tablets. Each member can interact with the lab equipment, which can be visualized in real-time by the instructor or fellow students. The system allows for real-time communication that fosters a truly collaborative environment. A comprehensive user study involving 72 participants (36 female, and 36 male) is conducted to evaluate the usability and learning impact of the proposed system. The participants were first year and second year undergraduate students (17 to 19 years of age) with an equal distribution over the two academic years. The user study employs both direct and indirect observations, combined with multiple surveys to collect both quantitative and qualitative data. The data analysis is performed from multiple viewpoints, and the collaborative AR learning environment is evaluated in terms of its usability, effectiveness of its collaboration functionality, and its impact on learning. Finally, the results also evaluate the feasibility of employing the system together with face-to-face learning.