I'm not sure whether you need the fourth value or not for name colours. In general, though, make it '1' - this is the Alpha value or transparency, and you'd only need it for partially transparent things.
R G B - Colour
1 1 1 - White
0.75 0.75 0.75 - Light Grey
0.5 0.5 0.5 - Mid Grey
0.25 0.25 0.25 - Dark Grey
0 0 0 - Black
1 0 0 - Red
1 1 0 - Yellow
0 1 0 - Green
0 1 1 - Cyan
0 0 1 - Blue
1 0 1 - Magenta (Pink)
For darker variants of the colours, change the 1's to numbers between zero and one. The first value is the amount of Red, the second is Green and the third is Blue. You can use things like a colour selector in MS Paint to make the colour you want, divide each value by 255 to get the values Blockland uses. Try experimenting to create different colours.
