Are the words "sundus" and "istabraq" Arabic or not?

The words "sundus" (fine silk brocade) and "istabraq" (thick silk brocade) are eloquent Arabic words because they are mentioned in the Holy Qur’an. Any non-Arabic words found in the Qur’an are there due to the اتفاق اللغات (concordance of languages). "Sundus" refers to fine silk brocade, and "istabraq" refers to thick silk brocade. It has been said that "sundus" and "istabraq" are Arabicized words from Persian.