It's clear that Afrikaners have significant Malay, Indian, and native ancestry, but I haven't been able to distinguish when the split that seems exclusively based on physical appearance happened. I would assume it is something that happened in varying degrees, with some distinction going back to the start of the colony and becoming finalised with apartheid.

From reading some research on a few notable slave women in the 17th century, I presume that what would later become racial status, at least between Europeans and their non-African slaves, was based largely on being Christian, which is similar to European attitudes in the Americas around the same time. I've learned of the changes to British laws in the Caribbean that replaced the language of Christianity with whiteness, did this process occur in a similar way in South Africa? Clearly, it wouldn't be a one-to-one comparison because slavery itself operated vastly differently in the two contexts. Also notable from reading the research previously mentioned, the term halfslag was very much used for the children of Europeans and non-Europeans, but I haven't seen it mentioned at all for grandchildren, and these children would be ancestors to both Afrikaners and Coloureds.

I spent a good afternoon looking at the genealogical data of the 17th century a while back and it looked to me that as long as someone was Christian, they reliably mixed freely with other Christians, regardless of the assumed appearances based on their parents and grandparents. Since the site I was reading only covers up to about 1700, I couldn't find as easily how that trend developed afterward. However, my family tree on the Huguenot side seems to have married exclusively other Huguenots for three generations after arrival in the Cape in 1690-ish, but this is only my ancestry and may not be reflective of the larger society. If I were to make guesses, I would assume that mixed marriages slowed in frequency once there was a large enough population of women of European descent, if I was to assume that the transition from religious identity to something more like racial identity occurred quickly, but that itself is what is unclear to me.

Lastly, I'm aware there are multiple ethnic groups under the umbrella term of Coloured and that my question largely relates to the Cape Coloured people as that history is what I'm most familiar with, but I'm interested in comparing the histories.