Carats and Karats

What is the history of both carat (diamonds) ?

What is the history of Gold Karat? Why 14k or 18k etc.? Why or
how did they decide what the parts of gold to other alloys?

Thank ing you in advance

Related Article:
Carats and Karats
By Sndra I. Smith 1996

Bruce Lipsey

Carats! not carrots!

the old method of weighing diamonds was using Carob-seeds. hence the
word “Carat”. English spelling has changed from the country of