The price of a cabochon is generally based on several facts regarding the material or mineral it is made of, such as the quality and/or rarity and popularity of the material, where it came from and size and/or weight, (measured in grams or carats). For example semi-precious stones such amazonite, onyx and aventurine are abundant and can be found and purchased in both freeform and calibrated sizes and shapes and are sold mainly by the piece. Rare jasper like Biggs Picture Jasper comes from a special location and the amount of work to find and cut a cabochon from a slab is time consuming, but it is a desirable material, popular, and is usually sold by the gram, (there are 28 grams in an ounce). Royal Lapis is another special material that can be sold by either the gram or by the carat, (there are 5 carats in a gram).
Pictured: Poppy Jasper cut and wrapped in 21-gauge Argentium wire by Beverly Brown