Artist/Maker: The "LAY" signature is the mark of an independent studio potter. Unlike high-volume commercial brands, studio potters often use personal hand-incised signatures or unique geometric stamps like this pentagon.
Glaze: You correctly noted that this is a smooth turquoise glaze, not a crackle or "fat lava" texture. This effect is achieved through a monochrome copper-based glaze that is fired to a mature, glassy state, resulting in a uniform, reflective surface rather than a fractured or bubbling one.
Clay Body: The base reveals a reddish-brown terracotta or stoneware clay [User Images]. The presence of small dark specks or "spotting" on the surface is likely due to mineral impurities in the clay body reacting with the smooth glaze during the firing process.
Form: The "bottle" shape—a bulbous body with a tall, slightly flared neck—is a popular silhouette in mid-century modern and contemporary studio art pottery.