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.
Tephrite is an igneous, volcanic rock, with aphanitic to porphyritic texture. Mineral content is usually abundant feldspathoids, plagioclase, and lesser alkali feldspar. Pyroxenes are common accessory minerals. Quartz and olivine are absent.