Opal mineral specimens from Coober Pedy, Australia exhibiting a vibrant blue colour with a vitreous lustre. The samples exhibit small amounts of opal within fractures in limonite, common for this mineral and has a schiller effect when viewed form certain light angles. Specimens are available in various sizes and come supplied in a card tray with an information label.
Opal is a well known mineral which has been present through out human history, most commonly as an attractive gemstone. It is however, a mineraloid, not a complete mineral, it can contain any where between 3% to 20% water and is deposited at relatively low temperatures in fissures, because of this, it is found in a variety of rocks but the most common and the samples which we stock are opal in limonite. It's structure allows it to defract light, giving it a schiller effect when held at certain angles, most opal is a vibrant blue colour though colours such as white, red etc have also been found. These particular samples come from Coober Pedy, Australia, a well know opal source, available in various sizes and supplied in a card tray with an information label.