Diamond Supplier?

I’m still in the start-up phase of my studio, I’ve registered the
business name and open a voluntary GST/HST account for tax purposes.
I’m part of the way there. I was at the local market this morning,
an old acquaintance asked what I was up to then followed with “could
I make him an engagement ring for around December?” I wanted to know:
where, or who are, suppliers for diamonds?

Thanks in advance for any direction or advise,
K. David Woolley
Diversiform Metal Art & Jewellery
Fredericton, NB, Canada