Amber (fossil resin)

Chemical formula: C10H16O (succinite), bears succinic acid (3-8%), common fossil remnants of flora and fauna (mostly insects).
Colour: from almost colourless through yellow, red, brown, bluish to black (rare). Most common are yellow and orange ("amber") colours of various saturation, what depends on th admixture of the organic pigments. 
Hardness: 2 - 3 according to the Mohs's scale, sometimes as low as 1,5. Brittleness varies significantly. The values of the absolute hardness varies for succinite from 17.66 to 38.40 kg per sq mm, for the "bone" amber 20 kg per sq mm, for "bastard" amber 25 kg per sq mm, for Carpathian amber 26 kg per sq mm. Melting temperature of succinite is 340 to 360°C.
Density: 1.07 +/- 0.2; plastic.
Cleavage: absent.
Transparency: from transparent to opaque.
Shine: glassy, resinous, fatty.
Refractive indice: n = 1.540