igneous
K2 stone (azurite–granite)
Biotite granite hosting blue azurite (Cu₃(CO₃)₂(OH)₂), often with malachite and quartz
AI-generated identification · may be incorrectPolished, dark gray-to-black granite with rounded vivid-blue azurite patches and pale quartz/feldspar veining; azurite hardness 3.5–4, granite minerals about 6–7, with vitreous to waxy luster. It is massive rather than cleaved overall; specific gravity commonly about 2.7–2.9.
Identified More igneous →
Explore K2 stone (azurite–granite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Polished, dark gray-to-black granite with rounded vivid-blue azurite patches and pale quartz/feldspar veining; azurite hardness 3.5–4, granite minerals about 6–7, with vitreous to waxy luster. It is massive rather than cleaved overall; specific gravity commonly about 2.7–2.9.
Formation & geological history
Formed as intrusive granite, generally Precambrian in age, later altered by copper-rich hydrothermal fluids near the surface to produce azurite. Commercial K2 stone is chiefly associated with the K2 region of Pakistan, near the China border.
Uses & applications
Used mainly as polished cabochons, carvings, slabs, and collectible lapidary material; it has limited architectural use because azurite is relatively soft and can weather or fade. Jewelry should avoid abrasion, acids, and prolonged sunlight.
Geological facts
The dramatic blue spots are azurite, not blue sodalite or lapis lazuli; white veining commonly consists of quartz and feldspar. The trade name “K2 stone” refers to the locality and appearance, not a distinct mineral species.
Field identification & locations
Identify it by a black-and-white granite matrix containing sharply contrasting blue spots, commonly with metallic copper-mineral flecks; azurite may turn green as it alters to malachite. Commonly sold from Pakistan through mineral and lapidary markets.
