Onyx decorative figure of a horse, private client
This onyx (calcium carbonate) figure was one of two that came into the workshop, with issues ranging from chips, breaks and losses to general dirt and aged adhesives from previous repairs.
The challenge here was restoring a missing ear and several small chips, and replicating the translucency, tone and sheen of the repair fills.
Whilst the term ‘onyx’ more correctly refers to a type of chalcedony (quartz) stone, it has also come to be used more generally to refer to softer stone such as this semi-translucent banded calcite.
Treatment began with the removal of yellowed repair adhesives and cleaning of surfaces, including the break edges of the neck, back feet and tail.
A replacement ear was modelled in plaster, based on the shape and size of the existing ear. This was then cast in a pigmented resin, and polished to match the existing stone. The repairs to the neck and feet were executed in a similar way. Great care was required to not damage the surrounding material during polishing, and most ‘making good’ therefore needed to be undertaken when the resin was still soft.
Cleaning of the metal chain, and reducing iron staining from around the horse’s mouth were undertaken both mechanically and by use of a weak chelator where necessary.