The cost of blue onyx stone slabs is influenced by several factors, including the uniformity of its color and pattern, the size of the slab, and the overall quality of the stone. Blue onyx slabs with a consistent and uniform color throughout tend to be more valuable and may command a higher price. The size of the slab also plays a role, as larger-sized slabs require more material and may exhibit larger, uninterrupted patterns, making them generally more expensive. The quality of the stone, including its clarity, translucency, and any unique characteristics, can also impact its price. Other factors such as market demand, availability, and the reputation of the supplier or quarry can further influence the pricing of blue onyx stone slabs.