Porcelain Streak Test for Minerals.
Size: 50 x 50 mm.
Sold in lots of 3 units. Minerals have physical properties which allow them to be distinguished from each other and which become identification criteria.
These criteria are precious, both for the specialist and for the amateur collector.
What first catches the eye is of course the color and crystal form of the minerals, but there are many other properties.
Many of these properties can be observed without the aid of instruments and are of great
