Black needle-like minerals run through the interior of the quartz. These are tourmaline or ilmenite, incorporated during the crystal's growth.

Over millions of years, the needle minerals crystallised first. The quartz then grew slowly around them, encasing what was already there. The direction, density, and thickness of each needle was set by conditions at the time. Those conditions never recur, so no two share the same arrangement.

A stone within a stone. Two minerals on different timelines, intersecting inside a single crystal.