The Death of “Organic”: Why Gemology Needs a Scientific Revolution

Session 2, Sarah Caldwell Steele
The Death of “Organic”: Why Gemology Needs a Scientific Revolution
Accredited Gemologists Association

by Emily “D.D.” Frontiere
for the Roskin Gem News Report

“Revolution” may seem like a strong word, but it is exactly what Sarah Caldwell Steele proposed that gemstone classification needs to evolve.

In her talk at the AGA 2026 Conference in Tucson, Sarah Caldwell Steele — Director of The Ebor Jetworks Ltd, Curator of Jet at Whitby Museum, and a PhD researcher at Durham University — explained to the audience that the label “organic” and the required descriptive criteria including RI values and the options for fluorescent color, are insufficient to describe both the origin and appearance of jet, the object of her studies.

To illustrate that an update to the term “organic” is long overdue, Steele spent some time explaining how the designation came to be. She referenced the first documented descriptions of gems by Pliny the Elder two millennia ago, saying that the careful explanations offered “may have been pre-chemical, but they were not pre-scientific”. Moving to the medieval period, Steele explained that gems like jet were considered living beings with both intellectual agency and the ability to reproduce. Later, during the 16^th century, the fields of alchemy and chemistry were interwoven, and it was observed that jet looked like wood but came from underground, leading to the philosophical question of how a tree could grow within the earth.

It was the post-enlightenment period when mineral classification matured and the idea of gems being alive was discounted. Soon after, during the Victorian period, inorganic gems were classified as crystalline and organics were non-crystalline. While this system was the best that nineteenth century scientists could come up with, Steele explained that it is insufficient, performing more as a “negative definition” which described what organics are not, as opposed to what they are.

Currently, the gemological definition of organic says that gems were created living plants or animals. Steele demonstrated that this narrow description does not account for the complex nature of jet whose creation process includes multiple living organisms as well as inorganic influences.

The specific constellation of circumstances that results in jet, Steele said, came together 183 million years ago on the ancient continent of Pangea. First, a tree had to fall into a river and be carried to the ocean. There, it became impregnated by the organic waste of plankton and algae which thrived in the heightened global temperatures that had been significantly elevated by the eruption of a super volcano. The impregnated wood was then buried and underwent further metamorphosis by heating within the Earth.

So, cumulatively, at least three types of living creatures and another three inorganic influences are responsible for jet creation. Does this make it an organic or an inorganic gem? In Steele’s words, “Whitby jet just broke gemology!”

Steele is not the first to recognize problems with the current definition of organic and try to implement changes. CIBJO introduced the term “biogenic” in 2016, which clarifies that organic materials such as pearls, amber, and mammoth ivory, were produced by a living animal or plant. While the adoption of this new term is a step in the right direction, it does not address the nature of jet. The problem with “biogenic” is that it classifies gems by their method of conception and does not take into account subsequent transformation(s).

So, the dual approaches of describing the nature of a gem by either the first step of its conception or its final form alone is not adequate.

Steele then explained that the magnitude of this problem is much greater than just unsatisfactorily describing jet. Employing the traditional gemological definitions, she said, only 250 unique minerals would exist on a dead planet with no biological activity. The existence of living organisms allows for more than 6,500 species, making biological activity “the primary driver of mineral diversity”.

Furthermore, humans have recently created a third category – “anthropogenic gems”. These are the synthetic gems like lab-grown corundum and diamond where humans have substituted themselves as the acting geologic agent using intelligence and technology.

With all of these factors at play, Steele said that the term “organic” is outdated not because it is just old, but because “it no longer maps onto reality. In a post ‘organic’ gemology world, we need to replace origin myth with a formation-centric framework. Look at how things form over time. What something was, to what it is.”

The revolution Steele proposes is not limited to championing “formation-centric” nomenclature, she also says that increased flexibility in describing gemstones is necessary. As a PhD student, Steele said that her formal written material, including her thesis, must use the currently accepted scientific terms and formatting in order to be defendable in front of an academic panel. The problem she faces is that jet, both its appearance and inherent properties, can’t be satisfactorily using traditional terminology.

For example, you can’t get an accurate RI reading on jet due to its reflectance suppression, but a number is required for a description to be considered complete. Additionally, when describing jet’s luster, one must choose between vitreous and sub-adamantine, neither of which is accurate. With regards to fluorescence, jet produces a tan color, but Steele says that she is forced to say it is red because “tan” isn’t a recognized term. Lastly, the famous streak which is the determining factor for jet identification is a ginger color, but since that word is not part of the standard vocabulary, and she has to use “orange”.

Moving forward, Steele said that information gleaned from multiple fields has to be taken into account when classifying gemstones – geology, chemistry, physics, and biology should all have a voice.

Following the presentation, the audience engaged in a spirited discussion about the meaning of the term “organic.” Clearly, the definition of the term is insufficient and has a range of interpretations that is unacceptable for standardized scientific purposes. Jet is a single gemstone, yet the issues that Steele raises extend far beyond Whitby. ◈

About the author:
Emily “D.D.” Frontiere is a gemologist, gems and jewelry appraiser, and freelance writer based in Santa Fe, New Mexico. You can read more of her work here as well as posted with the International Gem Society.
You can contact Emily “D.D.” Frontiere directly at: ddfrontiere@gmail.com.