It measures approximately 4 ¾ inches high (including burner) by 4 inches in diameter (at the base). The glass is in super shiny condition with no chips or cracks but does have some base wear. Not bad for a 100+ year old lamp! It has been irradiated to give it its beautiful deep purple/plum color an artificial process that turns antique clear glass in a beautiful deep amethyst/purple colored glass, it is about the equivalent of decades of glass overexposure to the ultra violet rays of the sun; the manganese which is one of the key ingredients that they used to take to get clear glass prior to 1910 reacts and becomes dark amethyst/purple in color, actually very few oil lamps have manganese in them and most are over 100 years old. Please take note that the color is not flashed on the glass nor applied, it is derived from the natural chemicals in the glass.
The brass burner is marked'BANNER / P&A MFG CO / Made in U. , it has its wick which seems to be in working condition. Please take note that a 2½ inches in diameter chimney/globe would fit but is not included with this lamp.