Silica is a very well known remedy. Its chemical name is Silicium oxide, or quartz.
Many people have written about this remedy, amongst them Sankaran and Vithoulkas, who have described different types of Silica. The group analysis can help us tie all these different aspects together.
Sand consists mainly of silicium oxide and is the basic material for glass and cement. Most houses in the world are made of stone, concrete, cement and natural stone, all of which contain large or very large amounts of Silicium.
Quartz is colourless and is Silica in its purest form. But there are many coloured forms too, such as amethyst, smoky quartz, rose quartz and citrine. There are also various forms of crypto-crystalline quartz such as onyx, opal, agate and heliotrope.