Medullary Rays in Oak: Nature’s Signature in Every Handmade Oak Staircase Component When it comes to staircase renovations, oak remains a popular choice — not only for its strength and durability but also for its beautiful natural features. Among these, one of the most striking and often misunderstood characteristics is the appearance of medullary rays. In this post, we’ll explore what medullary rays are, how they contribute to the aesthetic of an oak handrail or oak balustrade, and why they’re a hallmark of craftsmanship in every handmade oak staircase components we create.