This very attractive material is made from a ‘tagua nut’ which is picked up from the ground after forest animals have eaten all but the kernel, or harvested as fruit and the kernel extracted. As the nut hardens it shrinks and can be carved to make a variety of items.
The tagua nut from South America was brought to England in small quantities during the 1820s and 1830s but by 1887, it was recorded that the factories in London and Birmingham, England used two or three million nuts each year.
During the Victorian era, many items were crafted by hand-carving or turning on an ornamental or conventional lathe. These included thimbles and thimble cases with threaded lids, needle cases with threaded lids, tape measures with spindles, earrings, dice, and rings.
(Information with grateful thanks to Richard Mole Antiques.)