Complex sentence: Slave's fifth album, "Stone Jam", was their highest charting since their first, "Slave", and their second to be certified Gold, "Slave" received the certification in 1977.
Split into simpler sentences: Slave's fifth album, "Stone Jam", was their highest charting since their debut, "Slave". It was also just their second album to be certified Gold, "Slave" received the certification in 1977.