Properties of Natural Resins

CAMEO: Conservation and Art Materials Encyclopedia Online at www.mfa.org/cameo

Resin Source/type Melting Density Ref. Index Acid Saponification Solubility Characteristics Uses point (°C) number number

amber fossil resins 250-325 1.05-1.1 1.54 - 1.55 15-35 115-225 Amber is very resistant to yellowish, hard, glassy, fossil carved for jewelry, beads, acids and alkalis and is not resin; Mohs hardness = 2.5- amulets, and small vessels; entirely soluble in any solvent 3.0; Succinites emit succinic used as an ingredient in acid when heated; fluoresces paint and oil/amber a strong yellowish green to varnishes are made by bluish white in short-wave UV dissolving melted amber in light amber oil, turpentine oil, or a drying oil. copal diterpenoid resins from 180-340 1.04-1.13 1.528- 122-128 132-178 After melting, copals are May fluoresce white in short- varnishes for coaches, Trachylobium species (Africa), 1.545 soluble in oil and turpentine. wave UV linoleum, oilcloth, amber Hymenaea courbaril (South Soft copals are partially subsitute America) and Agathis soluble in ethanol, australis (New Zealand). chloroform, glacial acetic acid.

dammar triterpenoid resin from 90 1.04-1.12 1.515 - 16-18 20-65 Soluble in turpentine, oil, Darkens with age. Turns picture varnish, printing ink, Dipterocarpaceae trees in (softens); 1.539 chloroform and aromatic cloudy when moisture is mounting thin sections, southeast Asia of the genera 100-180 hydrocarbons present during preparation alkyd baking enamels, paper Shorea, Balanocarpus, or (melts); and textile coatings Hopea Tg =39.3

elemi from trees of the family 77-121 17.8-25 25-50 Soluble in ethanol, ether, Soft,sticky, odoriferous resin plasticizing additive in Burseraceae chloroform, benzene. varnishes; lithographic inks, Insoluble in water, turpentine paper and textile coatings, and mineral spirits. perfume bases, waterproofing mastic triterpenoid resin from mastic 95-120; 1.074 1.535- 50-71 82-92 Soluble in oil, turpentine, Darkens and become less picture varnish, additive in shrub, Pistacia lentiscus, in Tg =34.7 1.536 ethanol, diethyl ether, soluble with age. May turn oil media; printing ink, southern Europe and northern benzene, acetone, chloroform cloudy if moisture is present chewing gum Africa during preparation.

rosin oleoresinous exudate from 100-150 1.07-1.10 1.525- 150-180 150-200 Soluble in ethanol, acetone, Oxidizes easily and may paints, varnishes, inks, Coniferae trees (longleaf pine 1.548 turpentine, acetic acid, carbon blacken with age. adhesives, sealing wax, (Pinus palustris), Cuban pine disulfide Combustible, burning with a soldering fluxes, and (P. caribaea), loblolly pine (P. yellow, sooty flame. linoleum. Also used to taeda), cluster pine (P. increase sliding friction on pinaster), or Scotch pine (P. musical instrument bows and sylvestris)) dance floors

sandarac from the alerce tree Callitris 135-150 1.078- 1.545 140-155 143 Soluble in ethanol, ether, Brittle spirit and oil varnishes quadrivalvis native to 1.088 acetone, amyl alcohol and hot Australia and the sandarac alkali. tree Tetraclinis articulata native to northern Africa

shellac excreted by the female of the 115-120 1.035- 1.516 48-64 185-213 Fresh shellac is soluble in Iodine number = 10-18; furniture polishes, protective lac insect, Laccifer lacca, 1.140 ethanol, acetone. Shellac unbleached shellac will coating for plaster molds, native to India becomes insoluble with age autofluoresce orange; composition products; moisture can produce a white gramophone records haze on dried surface