石 is another pictograph character. From its current form, it can be dissembled into two parts, 厂 and 口. 口 is actually drawing of a stone, however if we just draw 口 to mean stone, it would be very confusing, as 口 can also mean mouth, gate and etc. Thus Chinese ancestors added 厂 ( which originlly means cliff, details please check our previous lesson of 厂) to mean this 口 is related to cliff, which gives 石, and it is then clear for us to know it means stone.
We can confirm our observation by looking at its evolution history (image yaken from http://www.vividict.com)
From Oracle Script of 石 - , I guess that it might contains other context inside this character. In ancient China, people lived in caves under cliff - . To prevent big animals from hurting them, people would put big stones - at the entrance to block them away. It is possible that is the original meaning of 石 actually? And such behavior of putting stone at the entrance of a house eventually became a habit, and along the time habit became culture. Chinese people started to place stone statues of lions and etc besides the gate to protect the household, as shown below:
That is it, 石 means stone.
And let us enjoy a Chinese calligraphy with 石 inside: