Rare Northwood Blue Victorian Decorated Glass Butter Dish. Circa 1900.  It does have an internal crack in the base.  We can find no place where this has been hit to cause this. We have shown a picture below.  It also has a tiny hard-to-see chip/flea bite on the rim of the top.  Ht. 6". This pattern was named Optica by Bill Heacock. The scarcity of this pattern is evidenced by the omission in the classic Northwood books as well as the Heacock series. It is an absolutely beautiful pattern which comes in two known decors. The positive attribution by Heacock was made based not only upon color but finials of the items. It is known in two decorations. There are two or three patterns issued by Northwood mentioned in ads that have not yet been identified. It is believed that this is one of them. This piece is electric blue, with inside optic panels, seen in the photo, which significantly adds to the pattern.