Why can’t you use this on low e glass?

Diamond Magic can't be used on low E glass because it contains actual diamond dust, which will scratch the Low E coating on the glass. 

can this be used on Low-E windows without scratching them?

We would not recommend using this product on any Low-E windows.

will this etch natural stone in showers or walls?

If the stone is polished, yes it will. We do not recommend this product for cleaning natural stone.

Is harmful for your health! ?

According to the SDS:

Harmful if swallowed. Causes skin irritation. Causes serious eye damage. Precautionary statements:
Wash hands, face and any skin contact thoroughly after handling. Wear protective gloves/eye protection/face protection. Do not eat, drink or smoke when using this product.
IF SWALLOWED: Rinse mouth. Call a poison center/doctor if you feel unwell.
IF ON SKIN: Wash with plenty of soap and water. Take off contaminated clothing and wash it before reuse. If skin irritation occurs: Get medical advice/attention.
IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Immediately call a POISON CENTER or doctor/physician. Get medical advice/attention if you feel unwell. See 4. First-Aid Measures for specific treatment. Dispose of contents/container to an approved disposal facility.

Check out the rest of their SDS for more info.

Is this product considered green?

Diamond Magic Stain Remover is not considered a green product, but if you are looking for a stain remover more eco-friendly, you can check out Bio- Clean Hard Water Stain Remover. It's non-chemical, non-toxic, biodegradable, and doesn't have any unfortunate scents or dangerous fumes.

Can this product be used on granite?

No, it is not recommended.

What is the consistency of this product? {Alcohol = 1, 2, 3, 4, 5, 6 = Molasses}

It's somewhere in the middle, maybe a little more fluid consistency than car wax.