Black Mica 10mm Round A Grade - 15-16 Inch 1.7mm At that time yellowish gems

At that time yellowish gems were called "topaz" in many parts of the world

Rhodonite belongs to the Pyroxenoid group of minerals

Opalite is known by several other names

It is the most abundant lithium-bearing mineral as well as a significant source of the rare alkali metals rubidium and caesium

Black Mica 10mm Round A Grade - 15-16 Inch 1.7mm At that time yellowish gemsMica is a mineral name given to a group of minerals that are physically and chemically similar. They are all silicate minerals, known as sheet silicates because they form in distinct layers. Micas are fairly light and relatively soft, and the sheets and flakes of mica are flexible. Mica is heat resistant and does not conduct electricity. There are 37 different mica minerals. The most common include: purple lepidolite, black biotite, brown phlogopite