What is a black onyx stone worth?

The value of black onyx can vary significantly based on factors such as size, quality, and craftsmanship. Generally, raw black onyx stones may range from $5 to $20 per carat, while polished or crafted pieces, like jewelry, can cost anywhere from $20 to several hundred dollars, depending on design and brand. High-quality, rare specimens can command even higher prices, especially if they are part of an intricate piece. Overall, it's essential to consider these factors when determining the worth of black onyx.