Take a look at the Obsidian image, and now try convincing yourself they are one and the same mineral.
Obsidian's dramatic, intense and fluid image is created by rapidly cooling lava because that is what obsidian is: lava.
From that you can understand the swirls of once liquified, high temperature lava, and the jet blackness coming from the colour of lava, but here the colours come from inclusions of other minerals to create a wonderful emotive image.
Whether it reminds you of fabric, only you can decide.
Obsidian is found all over the world from Easter Island to the Greek islands, and been used by proto-humans for over 700,000 years, but more recently for arrowheads, as a mirror, for ornaments, and even today as scalpels by surgeons as it is much sharper than steel.
As an artwork that it will continue to please.