Basically, anything flat. Many golfers use a coin.
As long as the ball isn't in motion and it is on the green, you can mark its position and wait your turn to play.
a marker that is flat so a ball can roll over it
No, you may only mark your ball when it is on the green.
yes you can
Yes
Not exactly. If his mark would be in your path, he can use any measuring device, (standardly his club length) to make the mark out of your line, and replace it to where it should be before he puts. He has the right to pick up his ball. AlthoughI guess you can always ask!
Golf ball markers come in various shapes and sizes. Under the rules of golf you can technically use anything to mark your golf ball on the green, you can use a tee, a pitch mark repairer or any coin. However good etiquette would be to use a small coin about 2-3 cm's in diameter and one that lies relatively flat to the ground as to not have any effect on your playing partners.
You can only mark your ball and pick it up when you are on the green. However, if lift clean and place is in play you may pick it up, but that is usually only in the winter.
Play the ball as it lies, you are only allowed to mark and clean your ball when you are on the putting surface (green). You would receive a two shot penalty if you cleaned your ball.
Ernie Ball
its not how you mark your ball, its how you mark your titleist.
You take a penalty stroke if you did not let te other player mark their ball.