Colorless Concrete

Concrete is one of the most common building materials in real life, so it's great that it is also available in Minecraft.  However, the vast majority of real-life concrete is unpainted, while all Minecraft concrete must come in one of sixteen vibrant shades.  This places many limits on realistic builds, so I suggest that a new type of colorless concrete, titled just "Concrete," is added to Minecraft.  It would be a very pale, dull gray color, and created with colorless concrete powder that is crafted out of sand and gravel.  Colorless concrete should also come in more forms than colored concrete: slabs, stairs, walls, as well as a brick version.