Uninterrupted Color Blocks is a mod for 1.8 (forge) that adds blocks in several different colors:
Orange, Green, Blue, Black, White, Yellow, Gray, Purple, Pink, Red, and Brown.
Note: Extreme simplicity is desired, so I will not be making better textures for the blocks. It is called "Uninterrupted Color" because there are no variances among the colors of the pixels in the textures.
Each block is made entirely of one specific color, unlike wool or clay with little variances. You can craft each block by getting Orange Essence from mining Orange which spawns naturally and crafting it with dyes. When you mine Orange, you get the block, but you can craft the block into nine essences. You can craft Orange Essence with:
Orange Dye, Cactus green, Lapis Lazuli, Ink Sac, Bone Meal, Dandelion Yellow, Purple Dye, Pink Dye, Rose Red, and Cocoa Beans.
There is also a weird block called Gradient. As long as you have mipmap levels set to 1 or above, Gradient has the following properties:
-it appears white when you are close to it
-it appears black when you are far from it
-as you move closer to or away from it, it will show a black to white gradation.

Gradient is crafted from a white block and a black block.
(All of the crafting recipes are shapeless; it doesn't matter where the required items are in the grid except for crafting nine Orange Essences into Orange.)

You can right click on a block with an orange essence in your hand to store the coordinates of that block in the description of that essence. Shift + right clicking with that essence will clear the coordinates. THIS STUPID FEATURE HAS BEEN REMOVED IN THE 1.9 VERSION OF THE MOD and I will post the older 1.8 version sometime soon.

Forge 1.9 is required for this mod. Use the recommended download at
http://files.minecraftforge.net/maven/net/minecraftforge/forge/index_1.9.html

For those who don't know, if you download forge do NOT click on the ad beneath the bar at the top of the page. Wait until it says "skip" in the top right and then click that and the download should begin.

How to install the mod:
Remove the jar file from the folder.
Put it in a "mods" folder in .minecraft in %appdata%
Open the launcher, and make a new profile with version forge 1.8 (install it if you don't have it already)
play