RuneScape talk:ProblemReports/22303

Technically, it's not wrong, as the prices for the onyx items are correct. However, nobody in their right mind would buy unenchanted onyx items, as the enchanted versions a lot less.

In my opinion, they should be kept in this calculator but specifically stated that the unenchanted onyx items (such as onyx ring, onyx necklace) are almost impossible to sell for those GE prices.