This butter dish features the McKee Aztec Sunburst pattern. The dish is 7 inches by 5 inches. The pattern was initially produced in 1910 by McKee Glass; later by L. E. Smith in the 1940s-1960s and then by Kemple Glass in the 1970s. There are 2 chips on the top rim of the dish.
The glass has been black light tested and fluoresces under the UV so it may be the earlier version of the pattern.