All our rocks are carefully selected for educational study. They come in labelled trays. The trays are normally 3" x 2" size depending on the rarity of the specimen. Average specimen size is shown below. These are ideal for classroom teaching and are a size that can be easily passed round the classroom for students to get a feel for each type.

Rhyolite is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained in texture, but may be porphyritic, containing larger mineral crystals in an otherwise fine-grained rock. The mineral assemblage is predominantly quartz, sanidine and plagioclase. It is the extrusive equivalent to granite

Scale cube=1cm: Full sizing please see photo

ACTUAL AS SEEN: The image shows the EXACT specimen you will receive. The specimen has been carefully hand selected and photographed. Measurements are as accurate as possible, though be aware measuring precise dimensions can be difficult from irregular shaped items. Whilst we portray colours as close to life-like as we can, colours will vary if taken in sunlight, indoors, from monitor to monitor and device to device. Once this specimen is sold, we will update this listing with new similar selected item, with a new photo and dimensions.*