There are 255 standard index colors and two additional color properties that are often referred to as colors (BYLAYER and BYBLOCK). You can use seven of the 255 standard index colors by name: red, yellow, green, cyan, blue, magenta, and white. (Numbers eight and nine are not named.) Each index color has a unique number from 1 to 255. The two additional color properties are BYLAYER and BYBLOCK. These color properties cause an entity to adopt the color either of the layer or of the block in which it is a member. BYLAYER is color number 256, and BYBLOCK is color number 0. In all commands for which you would use a color, you can indicate BYLAYER and BYBLOCK as well as by numbers 256 and 0, respectively.
To select an index color
Click Select Color in the desired dialog box, such as Layers, Properties, or Multiline Text. The Color dialog box opens.
Click the Index Color tab.
Click the color of your choice, or type the color number in the Current box.
COLOR: Sets the color for new objects
System Variables Reference
CECOLOR: Sets the color of new objects