Optics;
SPOT OPTIC (AKA)
• AKA: Inverted Thumbprint; IVT
Phoenix Glass Company (Monaca-PA, Operated: 1880-1894), Introduced: ca. 1883
• NOTE: Thomas Jiamachello - Phoenix Glass, "shoulder mould, spot optic pattern" (Marple p. 45-47). This blue is unusual for Phoenix. Made in the 1883-1887 period.
• Motifs: (Optics)