Sebright: Glauconite

The final colour of my pallet that was still eluding me had been green. My only consolation in this frustration is that it has been is shared by every artist going back hundreds of years. There just aren’t many naturally green pigment sources out there. Historically, an artist’s choice boiled down to either malachite (which is a copper, and I knew wasn’t going to be within the 100 mile limit) and terra verde – green earth.

To begin my search I contacted Pam Sangster, the Regional Resident Geologist for Southern Ontario. She was very helpful in answering my questions and generously devolved a secret location where she had found a mineral called glauconite which, in the pigment world, is called green earth. The photo above is hers and that thin crust of greenish crystals on the limestone is the glauconite.

The mineral glauconite is one of those that is wide spread, and most places have a little bit around, but in Ontario it is fairly rare. Traces of it can be found in Gull River Formation limestone. Pam’s find was a wonderful addition to this project and quite unexpected.

Green earth is best described as being grayish-green in colour. Historically, its use as a pigment goes far back into history; for example, it is one of the colours identified in a pigment set from a shop at Pompeii. While a green mineral, such as glauconite, is aways present in the pigment, ultimately this clayish pigment is a real hodgepodge of materials, and so every location presents a different variety of the colour. This has led to some types of green earth being named locally. A famous example of this would be Verona Green (which is green earth from just outside Verona).

Pam made an introduction for me to the owner, Mr. Eid Attia, and in a follow-up conversation with him he invited me up to Attia Quarry to scout around and see what could be found.