Fa-izan shaqqatis samaaa'u fakaanat wardatan kaddihaan

Word By Word:

Fa-izan: Then when

in shaqqati: is split

as samaaa: The Heaven

fakaanat: and it becomes

wardatan: rose colored

kaddihaan: like murky oil

Translation:

When the sky is rent asunder, and it becomes red like ointment:

Ayah Tafseer:

Melting away like grease or ointment. The red colour will be due to the flames and the heat. The whole of the world as we know it now will dissolve.

Source: Yusuf Ali Translations and Notes.