An image of the Sixth book within the Secretes of the Reverende Pietmont detailing instructions on whitening metals.

An Introduction to Metals and Gems

Throughout most of human history metal and gemstones have played a role in the development of society and technology. Silver, and gold are often associated with royalty or wealth. Iron, steel, and bronze are commonly associated with war and weapons. For gemstones diamonds cut in a certain way could be associated with a prestigious group among nobility , or perhaps the color of the gemstone one wore could discern who you believed to be worthy of being king [1].

No matter the reason one wore the gems or metals, the construction of precious metals and cutting of gemstones is mentioned throughout the Secretes of the Reverend Piedmont. The methods mentioned in this book include everything from cutting gems, gilding metals, to even faking gems from other less valuable gems. However due to the hazardous nature of the materials used in this book we will not be including a full list of ingredients and recipes.

Image of a raw diamond mined in Africa.

Common Metals and Gems in Renaissance Europe

Within the world of Renaissance Europe, new gems were being imported from all over the world; diamonds from India, and Africa; With sapphires, rubies, and emeralds coming from the Middle-East [2].

In addition to these new gemstones metallurgy and alchemy allowed for the creation, or more accurately,  decoration of metals. Typically these metals were iron, steel, silver and occasionally gold. With new mines being opened all over Europe, allowed for more experimentation for metallurgy [3]. 

With access to these materials being made more and more available, The Book of Secretes offers new insight into how the materials available would be used.

A gold necklace pendent with emeralds and diamonds. Circa 1550.

Making and Faking Gemstones 

Gemstones are often associated with wealth and fortune. In the past certain stones were associated with supernatural powers and nobility. In the book of secrets, more focus is placed on the actual creation of the proper cuts or styles of gemstones. For instance within the book there is a recipe detailing how to cut an emerald in the same style as done in Milan.

The recipe mentioned above requires the use of a variety of tools including a cutting stone (likely to be used as a grinder), a form of pitch to hold the gemstone, and various other materials that would have been relatively common for the time.

While cutting gemstones was popular, another recipe mentioned in The Book of Secretes is the ability to fake gemstones. One of the recipes mentioned is how to fake a diamond using a white sapphire. 

This particular recipe requires the use of all the tools mentioned above, however this particular endeavor also required dipping the white sapphire in molten iron. This process, while exciting and dangerous, may not have been used by many common folk. It is mentioned explicitly within the book that this trick is well known by most goldsmiths. This implies that many of these tricks used in the book were very well known by smiths as they were either commonly used tricks, or because the smiths helped with informing the author on these recipes [6].