This sounds like a physical separation question where there is a solution in which a crystalline precipitate has formed. The two techniques to separate the precipitate from the solution are filtration and evaporation.
The crystalline substances that are found naturally in the earth are known as minerals. There are literally hundreds of minerals on Earth that are used in everything from industrial purposes to consumption.
salt, sugar and ice
Caffeine is a bitter, white crystalline flaky solid in the purified form.
red blood cells
No, benzoic acid is a white crystalline solid and is not flammable. Like all organic substances though, it will burn with enough heat applied.
The crystalline substances that are found naturally in the earth are known as minerals. There are literally hundreds of minerals on Earth that are used in everything from industrial purposes to consumption.
salt, sugar and ice
Non-molecular substances can be bound more or less equally to all adjacent atoms in a repeating crystalline pattern.
This question is based on a false premise. Many crystalline substances are transparent, for example ice, quarts (in puure form, without falts etc.). Non transparent or translucant crystaline substances are probably so because of the way the crystal structure effects light entering the substance.
Diamond is pure, crystalline Carbon. It is one of the hardest natural substances known, and attributes it's hardness to an isometric octahedra crystalline structure which is very rigid and tough.
Mineraloids are mineral like substances that do not have a crystalline structure. Mercury is an example.
You might be thinking of hydrated salts. Examples include hydrated Copper Sulfate (CuSO4 . 5H2O)
Caffeine is a bitter, white crystalline flaky solid in the purified form.
Minerals are the components in the Earth that combine to form rocks. Minerals are inorganic naturally occurring substances, have a definite range of chemical composition, are solids, and have a crystalline structure.Minerals are solid, inorganic substances made from a combination of chemical elements.a solid, naturally occurring inorganic substance.
red blood cells
A function of the skin which helps to remove substances from the body is called perspiration, or sweat.
powdered substances have more surface area so they can be broken down quicker than substances with less surface area and that will cause the sustance to be absorbed quicker.