Go stones are stones that are used for playing the game of Go. They are usually biconvex in shape (meaning they look like three dimensional ellipses) and are usually only 2 cm in width. They come in two colors: white and black.
Go stones can be made from many different kinds of materials - with varying prices. Mass produced stones are simply white and black plastic counters or simple blown glass. Traditional Japanese stones are made from clam shells (for the white stones) and slate for the black stones. Stones can also be made from ivory or agate for the white stones, and onyx or ebony for the black stones.
Each board should come with 181 black and 180 white stones. That's one stone for every intersection on a 19x19 board, but generally games last fewer than 350 moves.
There are specific rules that one should follow around one's Go stones.
When not making a move, one should leave one's stones in the bowl. During the other player's turn, it is considered rude or offensive for players to vigorously shake or move their stones in the bowl. People also frown upon one holding many stones in one's hand at one time. The correct way to place a stone is to think of a move and then take a stone from the bowl and place it on the board. This lessens the amount of distraction that the other player would receive.
When removing a stone from its bowl to make a move, place a flat hand on the edge of the bowl, with the fingers gently entering the bowl. Pick up a stone with the index and middle fingers, holding the stone between the index fingernail and the middle fingertip. The fingers extend almost straight.
Make sure, if you are wearing long sleeves, to have them tucked in so that when you are placing the stone, you won't disturb already played stones, thus having angry players. To place the stone on the board, as soon as the fingertip of index finger is about to reach the surface of the board, it slips to the side, allowing the middle finger to aim the stone down towards the surface and connect (the other fingers and thumb naturally spread outwards).
Even though it is allowable for one to place a stone down loudly, it is not allowable for one to do that every turn. Doing so is considered rude and vulgar.
One should place one's stones in such a way that it would mimic what the player is feeling at the time. For example, when bowing down to an opponent's threat, playing a stone with little noise better; Probing moves or clever responses can be slid slyly into place. The ability to express oneself in the manner of making a move explains why one of the names for the game is "hand talk" ("shudan" in Japanese, "shoutan" in Chinese). 
Taking care of Go stonesEdit
New stones (of any variety except slate and clamshell) should be washed in warm (soapy) water to remove any oils or other products of their making or storage protection, then dried thoroughly. Do not use soap when cleaning clamshell stones; new clamshell stones should not need cleaning. New slate stones should be cleaned of excess mineral oil with a cotton cloth. When using stones, one should not slap the stones down too hard. When finished, they should be kept in either their bowls or original packaging and stored away from sunlight and heat. Placing a soft cloth in the bottom of the bowl can help to minimize chipping of stones.