Rock balancing or stone balancing (stone or rock stacking) is an art, discipline, or hobby in which rocks are naturally balanced on top of one another in various positions without the use of adhesives, wires, supports, rings or any other contraptions which would help maintain the construction's balance.
Rock balancing can be a performance art, a spectacle, or a devotion, depending upon the interpretation by its audience. Essentially, it involves placing some combination of rock or stone in arrangements which require patience and sensitivity to generate, and which appear to be physically impossible while actually being only highly improbable. The rock balancer may work for free or for pay, as an individual or in a group, and their intents and the audiences' interpretations may vary given the situation or the venue.
Rock balancing has also been described as a type of problem solving, and some artists consider it as a skill in awareness. Some work has been described as a magic trick for the mind. As with other forms of independent public art, some installations may be created in remote areas where there may be little or no audience. A cairn, used to mark trails, is also a collection of stacked rocks, but these are typically more durable.
(with classic balance detail)
The annual Llano Earth Art Festival in Texas includes a rock stacking competition called the "Rock Stacking World Championship," held on the banks of the Llano River. Competitions include "Height", "Balance", "Arches", and "Artistic merit". Rock balancing is also played as game in some parts of Nepal, where players make a tower of flat rocks and add round ones at the top.
The stability of a rock structure depends on the location of each rock's center of mass in relation to its support points. If other rocks are also on top or contacting it at any point, then the forces (due to weight) of other rocks also play a role. For an individual rock to be stable, it usually requires at least three contact points to rest on, forming a "tripod." Generally, the closer together the points in the tripod, the less stable the rock will be (thus making it more precarious, and becoming a rock balance sculpture - and many would argue more beautiful). Based on position and shape, a rock may also be stable even when resting on only a single point. A rock at the top of a sculpture, for example, can have a rounded shape, but be approximately flat and oriented horizontally, and be in a state of equilibrium.[nb 1]
The stability of a structure is also affected by the friction between rocks, especially when rocks are set upon one another at an angle. A structure may topple over (collapse) based on the magnitude of other phenomena, such as wind, rain, snow, and localized ground vibration, or general seismic activity.
Some visitors to natural areas who wish to experience nature in its undisturbed state object to this practice, especially when it intrudes on public spaces such as national parks, national forests and state parks. The practice of rock balancing is claimed to be able to be made without changes to nature; environmental artist Lila Higgings has defended it as compatible with Leave-no-trace ideals if rocks are used without impacting wildlife and are later returned to their original places, and some styles of rock balancing are short-lived. However, "Disturbing or collecting natural features (plants, rocks, etc.) is prohibited" in U.S. national parks, as these very acts may harm the flora and fauna dependent on them.
(A natural formation in El Tuparro National Park)