Chemistry Reference
In-Depth Information
TABLE 75
Natural Resins
Resin
Source
Uses
Vegetable
Amber
Extinct Pinus succinifera trees
Gemstone; varnish
Dragon's blood
Fruits of Daemonorop draco palms
Varnish
Dammar
Trees of family Dipterocapacaea
Torch fuel; varnish
Frankincense
Trees of genus Boswellia
Incense
Kauri
Agathis australis pine
Varnish
Labdanum
Cistus landaniferus trees
Incense
Lacquer
Melanorrhoea usitata trees
Varnish
Rhus succedaneae trees
Varnish
Rhus vernicifera trees
Varnish
Mastic
Pistacia lentiscus evergreens
Varnish
Rosin
Coniferous trees
Adhesive; varnish
Sandarac
Callitis quadrivalis trees
Varnish
Animal
Shellac
Secretion of Karria lacca insects
Varnish
Mineral
Gilsonite
A type of bitumen
Adhesive; lacquer
are usually hard, brittle, noncrystalline translucent solids. When struck, they
break with a conchoidal fracture, and if ignited, they burn with a sooty flame.
Only a few resins are soluble in water, the vast majority are not, but are
soluble in organic solvents such as alcohol. This makes most resins suitable
for use as
sealers
, protective coatings on porous materials such as wood, skin,
and textiles. Among the most widely used resins of vegetable origin are
amber
,
dammar
,
copal
,
dragon's blood
,
mastic
, and
rosin
, all of which are either
exudates from living, dead, or even fossilized plants, or extracts from the
stumps or heartwood of living trees. Table 75 lists natural resins that have
been used since ancient times.
Amber.
Amber
is a relatively hard, transparent, or translucent fossil resin
that was exuded during the Oligocene geologic period (over 25 million years
ago) from now-extinct coniferous trees of the species
Pinites succinifer
. It gen-
erally occurs in irregular rod- or drop-shaped accumulations whose color
may vary from shades of yellow, through brown, to orange, and occasion-
ally red. Its main constituents are a mixture of organic substances that
include carbohydrates and succinic acid (Fraquet 1987). Amber is easily
