The resin exuded by the North American lac scale insect Tachardiella larrae Comstock has been used in the past by peoples of the Great Basin region as a sealant, an adhesive, a modelling material, and for medicinal purposes. Such use has been reported ethnographically, but identification of the resin surviving on archaeological materials has been problematic until recently. This study seeks to examine the chemistry and use of the resin by examination of its working properties and through the application of a range of analytical techniques to authentic, experimental, and archaeological samples.