Well, if you are apparently ignorant like myself you would say “White” or maybe “Shades of Grey”. This US Government website has a kind of “Google Moon” app which uses photographs from the 1994 Clementine project – which was a satellite sent to The Moon to capture images of its surface.
http://pdsmaps.wr.usgs.gov/PDS/public/explorer/html/moonpick.htm
Choose the 2nd option “Natural color” and then click on an area of The Moon to zoom in. There’s plenty of Brown there, and you can see quite a lot of Blue too.
I am curious though as to why during Apollo 8 when asked what The Moon looks like the response was "The moon is essentially gray, no color; looks like plaster of Paris or sort of a grayish deep sand". Page 361
Which is one of the reasons that Alan Bean's art (Apollo 12 moon walker) has always confused me - why does he paint The Moon Brown? Seems like now I know, but that Apollo 8 statement was odd to say the least.