Taboo Numismatics Part IV: Comparison of the coinage of Christian Byzantine Emperor Justinian II, 685-692 CE [Left], and that of the Muslim Umayyad Caliph Abd al-Malik 693 CE (AH 77) [Right]

Two coins from roughly the same time period - the Muslim Abd al-Malik coin [on right] minted slightly later than the Christian Justinian II coin [on left]. The Islamic coin is clearly copying the earlier Byzantine coin, except of course, that it doesn't depict the face of Christ on the first side.

As well, on the back side, the left coin is thought to be a portrayal of the great jeweled cross erected in the Church of the Holy Sepulcher in Jerusalem on site of the Crucifixion. The Islamic coin on the right, conversely, shows a single column with a ball on four steps, stating: "There is no God but God and Muhammad is the Apostle of God." (The Muslim profession of faith) and "Damascus Year 77" (Islamic year 77AH). The single column is a symbol of the 'oneness' of God, as opposed to the cross potent, which is a symbol of the Crucifixion of Jesus the Son of God, and a symbol of the Trinity, both of which Muslims vehemently deny.

More details at the link above.