Horsetail is the plant at the top of the list when it comes to naturally occurring sources of silica in plant form. Horsetail also has many other species, so be sure to check the Latin or botanical name. Often when researching horsetail, it is in fact Equisetum Arvense instead. Searching by Latin name ensures you order the correct product. This is sustainably wild harvested by myself from my property in Eastern Oregon. This listing is for ( 1oz or 2oz ) ground. Due to the high silica content equisetum hyemale is extremely hard on grinders. My grinder does a pretty good job but if you need it finer you can put it in a coffee grinder that hasn't been used for anything else. If you need a different amount please contact me. This item only ships within the USA until further notice. People have used it in their tooth powders, teas, tinctures, or ground and put into capsules. Information provided on herbs are for educational purposes, not to be considered medical advice. This product has not been evaluated by the fda. Not intended to cure, treat, diagnose any illness. Always do your own research.