Muscat is actually a family of grapes that has over 200 varieties, with skin colour varying from dark to light. Italian ones, for instance, are yellowish-green and large.
Other varieties include Muscat Canelli (aka Muscat Blanc), Muscat Blancs à Petits Grains, Muscat of Alexandria (aka Moscatel Romano), Muscat of Datal, Orange Muscat, Early Muscat and Black Muscat (aka Muscat Hamburg.)
The United States Department of Agriculture development programme in Fresno, California has recently (2000 & 2001) developed seedless Muscat grapes (Selma Pete and Diamond Muscat.)
Muscat grapes are widely grown near Fresno, California.
The White Muscadelle Grape from Bordeaux, despite the name similarity, is not actually part of the Muscat family.