
The medallion you have is a "Genootskap van Regte Afrikaners Medallion" issued by the South African Historical Mint. This medallion commemorates the centenary of the "Genootskap van Regte Afrikaners" (Association of Real Afrikaners), which was formed in 1875 to promote the Afrikaans language.
The value of this medallion largely depends on its composition:
* 18ct Gold Medallion: These medallions, typically weighing around 38.4 grams, are much more valuable. Recent sales and listings show these ranging from $1,200 to around $3,789 USD (or equivalent in ZAR). They usually come in a blue case lined with white silk and blue velvet and have a numbered certificate, with a limited mintage of 1,500.