RE search vs index

I have used quiltshops.com several times but never the index part. I find it is better if you know the manufacturer rather than a general subject unless it is specific like cardinals or pumpkins or cats. Yes, if you put in a color adjective,you will get every fabric that color. But try defining your sky--how about cloudy sky or watery sky. Or try "blue marble" with the quote marks or "blue strata." There are a lot of fabrics meant as water that also make wonderful skies. Light tone on tone batiks might also be pretty.

Another source for fabrics is ebay. You don't have to buy there, but if you put in sky fabric on ebay you are more likely to find things you want and often the description will tell you the manufacturer or the fabric line.

Hancocks of Paducah also has their fabric linked to a keyword. Again, you don't have to buy there but you might find fabrics that would work that you can keyword in elsewhere.

Hope this helps!