The diameter of the coin was {{cvt|1|inch|mm|1}} throughout Charles II's reign, and the average gold purity (from an [[Trial of the Pyx|assay]] done in 1773 of samples of the coins produced during the preceding year) was 0.9100. "Guinea" was not an official name for the coin, but much of the gold used to produce the early coins came from [[Guinea (region)|Guinea]] in Africa.
The coin was produced each year between 1663 and 1684, with the elephant appearing on some coins<ref name=EB1911/> each year from 1663 to 1665 and 1668, and the elephant and castle on some coins from 1674 or 1675 onwards.<ref name=EB1911/> onward. The elephant,coins withwere ornamed withoutfor the castle[[Gold Coast (region)|"Guinea" Coast]] region of [[West Africa]], symboliseswhere the gold for the coins were imported from by the [[Royal African Company]] (foundedRAC); inthe 1660)company's symbol, whosean slave-tradingelephant, activitieswas featured on the Guineacoins Coastsourced offrom Africagold resultedimported inby the importation of much gold into EnglandRAC.<ref>{{cite book |last1=Margolin |first1=Sam |chapter=Guineas |editor1-last=Rice |editor1-first=Kym S. |editor2-last=Katz-Hyman |editor2-first=Martha B. |title=World of a Slave: Encyclopedia of the Material Life of Slaves in the United States |url=https://books.google.com/books?id=T4_Qaju1WyoC |publisher=ABC-CLIO |publication-date=2010 |page=259 |isbn=9780313349430 |access-date=2015-02-08 |quote=The coins were named because much of the gold used to produce them came from the Gold or 'Guinea' Coast of West Africa and was provided by the Royal African Company, which had been granted a monopoly of the Africa trade from 1672 until 1698. Coins produced from African gold bore the company's distinctive emblem below the monarch's head: an elephant or elephant and a castellated howdah, an ornate canopied seat used for riding on elephants and camels.}}</ref>
