A petroglyph is an image somehow cut into the rock. It can be carved, chipped or somehow embedded into the stone in any other way that pre-historic people could.
|Petroglyph from http://www.petroglyphs.us|
A pictograph is an image that is painted onto the rock. Different types of earth, charcoal, ground stones or plant matter were mixed with a medium, usually animal fat, to adhere the pigment to the stone.
Ideograms are pictures or symbols that convey an idea or concept. For example, how would you draw heat or warmth? They really aren’t visible, physical objects that you can depict, although you physically feel them. You might draw a fire or the sun, but you really aren’t talking about those objects specifically -- you are communicating something that comes from them.
|Native American ideogram for Bear Dead|
|Native American ideogram for Bear Alive|
from the website
Found on all continents, petroglyphs, pictographs and ideograms are a form of pre-writing. All do not represent words or sounds of a language. We don’t believe they were made for artistic reasons, but for:
a) utilitarian purposes such as an animal painted to use in a hunting lesson;
b) religious or magical rites such as pre-hunting rituals to gain power over animals; or
c) other cultural reasons lost to the sands of time.
A logogram is a picture or symbol that represents an actual word in a language – not just the idea of it. This implies that there is cultural agreement that the symbol means this sound or series of sounds, which in turn means something. So the ideogram you drew for heat could evolve into a logogram if your clan agreed that it meant the word heat – not just the idea of heat. Logograms are examples of word-writing, and many writing systems used logograms, including Chinese, Egyptian hieroglyphics and cuneiform.
|from the website:|
However, all languages include at least some symbols that represent a particular sound or group of sounds in a language. These are called phonograms, and do not necessarily represent words. For example, names in Egyptian hieroglyphics were written using phonograms, basically showing how they sounded, and then encircled to group them together. Every letter of the English alphabet is a phonogram.
|from the website|