Young amber to protect the pulp
The name “copal” has become something of a collective term for fossil and recent resins of varying characteristics and botanical origins. Copalli is a loan word from Nahuatl, the ancient Aztec language, with which the Native Americans described smoked resin, which was sacrificed to Gods on their altars. Optically, copal is quite similar to amber and can sometimes contain trapped insects or other small creatures, which makes it therefore a popular collector’s item. Copal can be almost colourless and transparent or take on a lush yellow to red-brown tone.
Fossil copals can be found in almost all parts of the world, in deposits a few meters under the ground. They can be thousands of years old, but are still rather young in comparison to amber, which can be several million years old. These natural resins originate from the damaged bark of conifers or leguminous (pulse) plants. Copals are usually described according to their origin, such as Zanzibar Copal or Manila Copal, and only sometimes according to the plant from which they originate, such as Kauri Copal, named after the New Zealand kauri fruit (agathis australis). East African copals are said to be the ones with the highest quality, as their characteristics come closest to those of amber. Fossil resins, also known as mature copals, are hard, hardly soluble and difficult to melt. Recently extracted copals, such as tree copal, which is directly harvested from trees as fresh resin, are much more important for industrial processing.
At the beginning of the 20th Century, thousands of tons of copal were transported to Europe for the production of varnishes, where the hardest copals were used to make the most resistant varnishes. Today, however, mainly synthetic materials are used in the varnish industry. Copals, like natural resins in general, are today only used in cases where old techniques are implemented (especially in painting) or where environmentally friendly materials are needed (such as linoleum manufacturing).
The copals used by Hoffmann Dental Manufaktur for the varnish with the same name, are recently obtained copals from Indonesia. Copal is liquefied with ethanol and receives a lighter or darker colour according to its colour composition, similar to a Single Malt Whisky.
Copal is used for the production of thermoplastic impression compounds, and gives the products their typical shine and firmness. Copal varnish particularly serves as a cavity varnish to protect the pulp.
