What is K2 Stone?

K2 Stone: A Distinctive Material from Pakistan

K2 stone is a fascinating rock named after the world’s second-highest mountain, K2, where it's found. K2 is part of the Karakoram Range, near the border of Pakistan and China.

It was initially reported to be white granite with distinctive, orb-like markings of blue azurite. In some K2 stone, the azurite is so distinctive that it resembles blue dye. Occasionally, subtle traces of malachite can also be seen.

Although often marketed as 'K2 crystal' or 'K2 Jasper', these names are geologically incorrect. The word 'crystal' is a trade name, widely used for rocks and minerals used for their metaphysical healing properties.

Describing it as K2 Jasper is incorrect, because jasper is a type of microcrystalline quartz (chalcedony), which is a different material.

K2 stone grades 6 on the Mohs scale of hardness, but it can be prone to visible signs of wear if not handled carefully.

It's found at the base of a steep slope in a rarely visited part of the Karakoram Mountain Range. When it first appeared on the market some years ago, geologists were not convinced the blue spots were natural.

A thread on Mindat, the world’s largest online mineral database, discusses the blue staining in more detail.

After scientific testing, the following results were reported:

• Blue spots: These marks are believed to be azurite. The grains show high birefringence, meaning they bend light in two directions. This property makes their optical characteristics harder to analyse under a microscope.
• K2 stone is composed of:
  • Microcline – a type of feldspar, often pale or pinkish
  • Quartz – clear or white crystals, common in many rocks
  • Biotite and muscovite – two types of mica, flaky and shiny
  • Plagioclase feldspar – another feldspar variety

The host rock is not true granite. It's more accurately described as granite gneiss or, in some analyses, as alkali feldspar quartz gneiss. Both are metamorphic rocks that have undergone heat and pressure. It likely began as granite or granodiorite before being geologically altered.

So, K2 stone is a metamorphic rock with azurite inclusions, formed through complex geological processes that caused its distinctive appearance.

It’s generally believed that the blue spots in some material from China have been enhanced.