‘Optal’ and ‘opal’ are variants of the same word, derived from the Greek word ὀπάλλιος, which, can be traced back to the Sanskrit word for ‘precious stone’. The ‘t’ in ‘optal’ is believed to have been added in post-classical Latin under the influence of the Greek word for ‘eye’, ὀϕθαλμός, because of the stone’s alleged positive influence on the eyes (FEW 7,258b note 1). Based on the source material analysed for AND², the variant form without a ‘t’ does not appear to be attested in Anglo-Norman.