Stone ball

Short description: Spherical stone of natural or artificial origin

A stone ball, or "stone sphere", is a spherical stone object that may be of either natural or artificial origin. Different types of stone balls include:

## Natural

* Natural Stone Balls
* megaspherulites
* cannonball concretions
* Moeraki Boulders
* Rock City, Kansas
* Torysh, Kazakhstan
* Moqui marbles
* spherical corestones created by spheroidal weathering
* Cave pearls

## Artificial

* Artificial Stone Balls (Petrospheres)
* lapidary spheres
* Lithic-Bolas
* stone round shot (cannonballs)
* Ammunition column
* spherical stone shot for trebuchets
* Stone spheres of Costa Rica
* Carved stone balls from prehistoric Scotland
* Kugel balls

## External links

Stone round shot (cannonballs)

* Ruffell, W.L., 1996, The Gun - Smoothbore Era 1550-1860: Projectiles Royal New Zealand Artillery Old Comrades' Association, New Zealand.

Stone balls (spheres) of Costa Rica

* Hoopes, J.W., 2005, The Stone Balls of Costa Rica University of Kansas, Lawrence, Kansas.

Carved stone balls of Scotland

* Hunterian Museum and Art Gallery, nd, Carved Stone Balls A gallery of carved stone ball photographs & information
* Marischal Virtual Museum, nd, ball, carved stone Aberdeen Museum's virtual gallery of their Carved Stone balls

Megaspherulites

* Baird, Bill, 1990, Stone Spheres, The Edinburgh Geologist, no 24 (Spring)
* Heinrich, P.V., 2007, Megaspherulites. PDF version, 1.4 MB BackBender's Gazette. vol. 38, no. 7, pp. 8-12.
* Rodríguez, E.A., 2002, The fantastic balls in el Cerro Piedras Bola (Jalisco), México desconocido # 305, July 2002. Last visited February 11, 2008.
* Smith, R.K., R.L. Tremallo, and G.E. Lofgren, 2000, Megaspherulite Growth: Far From Equilibrium Crystallization, GeoCanada 2000 - The Millennium Geoscience Summit, Canadian Society of Exploration Geophysicists Annual Meeting.
* Smith, R.K., R.L. Tremallo, and G.E. Lofgren, 2001, Growth of megaspherulites in a rhyolitic vitrophyre, American Mineralogist. vol. 86, pp. 589–600.

Cannonball concretions

* Hanson, W.D., and J.M. Howard, 2005, Spherical Boulders in North-Central Arkansas PDF version, 2.8 MB Arkansas Geological Commission Miscellaneous Publication n. 22, pp. 1-23.
* Heinrich, P.V., 2007, The Giant Concretions of Rock City Kansas PDF version, 836 KB BackBender's Gazette. vol. 38, no. 8, pp. 6-12.
* Irna, 2006, All that nature can never do, part IV : stone spheres
* Irna, 2007a, Stone balls : in France too!
* Irna, 2007b, Stone balls in Slovakia, Czech Republic and Poland
* Leo Gav, 2007, Underwater stone balls
* Hokianga Tourism Association, nd, Koutu boulders Really nice pictures of cannonball concretions.
* United States Geological Survey, nd, cannonball concretion