Carel Christoffel Rykvoet (originally Carl Christoph Rauchfusz) was the son of Christiaan Ernst Rykvoet and Anna Justina Steyn. came to the Cape of Good Hope around 1745, probably as a military surgeon. In October 1746 he must have obtained his discharge from the military, for he was practising as a burgher surgeon and apothecary in Stellenbosch. For some time he combined his medical practice with farming, for in the census of 1751 he is recorded as having produced ten leggers [5820 liters] of wine from 32 000 vine stocks. As a burgher he did military service as a dragonder (mounted infantryman) in the Compagnie Invalides at Stellenbosch. On 8 October 1747 he married Johanna van Ellewee, with whom he had two children. In 1752 the family moved to Cape Town, where his wife died early in 1758. He was married for the second time on 3 September 1758, to Maria D. Heyns.
In 1761 he accompanied a government sponsored expedition, led by Hendrik Hop, to Namaqualand and southern Namibia. His brief was to report on the mineralogy of the regions visited. Other members of the expedition included the surveyor C.F. Brink* and the gardener J.A. Auge*. The expedition left on 16 July 1761 and returned on 27 April 1762, having reached a point some 70 km east of Keetmanshoop. On 4 May 1764 Rykvoet reported briefly on his finds to Governor Tulbagh. He found the "Copper Mountain" visited by Governor Simon van der Stel* in 1685 to contain only a small quantity of ore. However, close by he found richer deposits, which it might be possible to mine if sufficient wood and water were available. Most promising were copper deposits close to the Orange River in what is now the Richtersveld, but he considered even these uneconomical owing to the hardness of the rock, insufficient fuel to smelt the ore, and transport problems. His report, "Behelzende de gesteldheit van het gebergte en de daarin gevondene ertzen, dewelke op de jongstgedaanen togt door het land der Namacquas zyn ontdekt geworden" (Concerning the nature of the mountains and the ores found therein, which were discovered during the recently conducted journey through the land of the Namaquas), was included as an appendix to Brink's account of the expedition, published in 1778 as Nieuwste en beknopte beschrijving van de Kaap der Goede-Hope. Many years later an English translation of Rykvoet's report was published in the South African Commercial Advertiser of 18 March 1846.
In April 1766 Rykvoet returned to Stellenbosch and resumed farming, but died two years later.