Quite unusual for Riihimaki, this is made from neodymium glass (also known as alexandrite glass), which changes colour according to different lighting conditions. It appears lilac in natural sunlight or yellow artificial light, and smoky blue in fluorescent/white light (see pictures).
This is due to the presence of neodymium oxide (Nd²O³) in the glass. 5 inches tall by about 4 inches in diameter. Please reach out with any additional questions!