What are some natural, but man-facilitated types of jewels?

I should clarify, I’m looking for items that either come from nature, and are quickly renewable or plentiful, such as pearls, or sand for glass, but when producedor transformed, take on new dimensions of value.

We can now make perfect diamonds out of carbon, much to deBeer’s dismay.

And there are emeralds and other precious gems made in the labs. The insides of sea-shells have nacre or mother-of-pearl that can be used for beautiful inlay work.

Synthetic gemstones

Silk.
Possibly ambergris.

Isn’t Cubic Zirconia kind of a man made “diamond?”

Oooh silk’s a good one, and sea shells too. Any others like these?

Diamonds and precious gems are less interesting just because they require very expensive machinery and chemistry—so it’s human facilitated to the nth degree. Looking for processes that are less capital intensive, more manual labor/effort.

Amber, small geodes, wampum, and small sea fossils like sand dollars. (I can’t imagine wearing a necklace of caviar, however.)

Moissanite! My engagement ring is moissanite and I wouldn’t trade it for anything. We chose it over a diamond. It’s clearer and more brilliant than any diamond. They’re beautiful, and a fraction of the cost. I hope to one day have matching earrings.

genitals?

How about tequila into diamonds?

Scientists Turn Tequila into Diamonds

(PhysOrg.com)—Whoever thought that science was a dry subject might change their mind after learning about a new discovery in which tequila is turned into diamonds. A team of Mexican scientists found that the heated vapor from 80-proof (40% alcohol) tequila blanco, when deposited on a silicon or stainless steel substrate, can form diamond films.

There are certain very beautiful metal alloys, such as vermeil, elecktron and red gold which are made of natural elements manipulated by human ingenuity. There are also certain wooden objects where the basic shape was created by manipulating the growth of a living tree; I have a chair that was formed that way.