Limestone

Limestone should be added as another stone type. Many real world buildings use limestone in their construction, and there currently isn't a block in game that matches well to that color. The color should be between that of stone and sandstone. This block would generate under the sand and gravel in ocean biomes, mirroring the real world carbonate shelf. This block could be crafted using one calcite and one cobblestone. Like other stone types, it would have a polished, chiseled, and brick variant. Adding this stone type would be an opportunity for Minecraft to further educate players about real world geology in addition to expanding its block palate.