LR# 166-B is a clear EAPG cup plate. It is in the chapter "The Lacy Period, 1830-1845" in the book "American Glass Cup Plates" by Ruth Webb Lee and James H. Rose, where it's rarity is listed as "scarce". The photograph is on page 132, and the description is on page 143. The diameter is 3"; the rim is plain rope on the top-only.
There is a dark spot within the glass; aside from that it's in very good condition. It's origin is the Midwest. The center has 12 point star, with a bull's-eye at the end of each point. The shoulder has six daisies alternating with swirls. The edge is smooth.
Cup plates were very popular from the 1826 into the 1850's in America. They performed many purposes, as a coaster for a tea cup; they helped prevent tables from being marred, and also kept the table linen clean, and acted as a cooling medium to the hot cup of tea.