SURFACE LUSTRE 143
All that
glisters is
not gold
William Shakespeare
The Merchant of VeniceSatin spar
Satin spar normally displays a silky
lustre, which is caused by
microscopic inclusions.Kaolinite
This clay mineral’s
lustre is earthy. It is
not gem-quality.Mother-of-pearl
Not surprisingly, the lustre
of mother-of-pearl is defined
as pearly. This material
is also known
as nacre.Malachite
Malachite material features
a lustre that is defined as
adamantine to silky.Amber
Amber has a resinous lustre,
resembling the smooth surface
of plastic. It is an organic gem,
formed from tree resin.Turquoise
The surface of turquoise generally
has a waxy lustre, though this can
range to subvitreous.142-143_FEA_Lustre.indd 143 19/05/2016 14:44