SB 12.11.10
kaustubha-vyapadesena
svatma-jyotir bibharty ajah
tat-prabha vyapini saksat
srivatsam urasa vibhuh
Translation:
Upon His chest the almighty, unborn Personality of Godhead bears the Kaustubha gem, which represents the pure spirit soul, along with the Srivatsa mark, which is the direct manifestation of this gem’s expansive effulgence.