You can download $model.originalFormat files of 20 High Res Seamless Granite Textures Vol.01 3D model from www.exchange3d.com. Direct link to the 3D model: Exchange3D media store More details: 20 large 3000x3000px perfectly tileable granite textures.
Perfect for kitchen tops, facades, flooring etc.
You can slice them to different pieces to make tiles.
You can also texture stones and rocks with them.
Some can even fit for a planet texture.
Quality of the JPG: 97%. The model preview: