In Hindu iconography, Goddess Saraswati is depicted as holding a akshamala – a mala or string of 51 pearls or crystal beads or rudraksha. The akshamala of Goddess Saraswati symbolically suggests that she is the patron goddess of learning and knowledge.
The 51 beads symbolically represents the number of vowels consonants in the Sanskrit alphabets.
Akshamala in the hands of Goddess Saraswati symbolises the disciplined, dedicated and devout attitude of prayer and meditation.
The pearl or crystal beads also testify to the overwhelming presence of sattva guna or purity, and luminosity of Goddess Saraswati.
Notes taken from book titled - Kamandalu: The Seven Sacred Rivers of Hinduism