The raw Rock Crystals that have been threaded for this gemstone strand have a size of about 15 - 25mm. So that the finished stone necklace is good to wear, the raw stones were drummed and therefore have no sharp edges and corners.
The strand is about 40cm long, the Rock Crystals partly show brown inclusions of iron oxide.
Gemstone healing uses Rock Crystal to strengthen one's point of view and increase clarity of thought.