Among the Balts, the connection between the sun and spinning is very old, and the sun-stone, amber, forms the link. Spindles of amber have been found in the most ancient burial mounds. Sometimes amber discs were also placed in the grave, perhaps as prayers to the Sun Goddess to spin forth the lost life in another body. No doubt some of these spindles were used before being buried, for amber was considered a magical substance for a spinner; as the light never tangles in the sky, so an amber spindle protected the new thread from snarls caused by unhappy or malicious spirits.
Source: The Blue Roebuck
“The greatest goddess of the Baltic peoples—the Lithuanians and Latvians—is the shining sun, the sky weaver, the amber goddess Saule. She rules all parts of life, from birth into her light to death when she welcomes souls into her apple tree in the west. Saule is worshipped each day when her people bow to the east to greet Mother Sun.”