Are the Sango coral capsules really 100% natural?

Capsule contents:
Our Sango coral capsules consist only of Sango coral powder (90.4%) and the capsule shell. The Sango coral powder is a natural product with over 70 minerals and trace elements. It is filled into the capsules unchanged, is not an extract and no chemical substances are used. Since this is a protected manufacturing process, we are unfortunately not allowed to pass on any detailed information here. However, we can assure you that the production takes place under strict quality standards and does not use synthetic agents.
Shell:
Hydroxypropylmethylcellulose (HPMC) does not occur in this exact form of cellulose in any specific plant. To produce it, cellulose, which is the basic structure of all plants and is obtained from nature, is processed. Cellulose is similar in structure to sugar or starch, except that it is indigestible for humans. In this context, indigestible means that it swells with moisture but is not absorbed but excreted after passage - like all fiber. The processing gives the cellulose additional properties, e.g. it becomes water-soluble. This is important so that the capsule can dissolve. HPMC is very popular in the production of food because it is a well-tolerated, plant-based and harmless substance. It is used, for example, as a capsule shell or to give food consistency.