A crystal or crystalline solid is a solid material
whose constituents (such as atoms, molecules, or ions) are arranged how?
A: In a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.
In addition, macroscopic single crystals are usually
identifiable by what?
A: Their geometrical shape, consisting of flat faces with specific, characteristic orientations.
The scientific study of crystals and crystal formation
is known as what?
What is the process of crystal formation via mechanisms
of crystal growth called?
A: Crystallization or solidification.
Examples of large crystals include what?
A: Snowflakes, diamonds, and table salt.
Most inorganic solids are not crystals but what?
A: Polycrystals, i.e. many microscopic crystals fused together into a single solid.
Examples of polycrystals include what?
A: Most metals, rocks, ceramics, and ice.
A third category of solids is amorphous solids, where
the atoms have what?
A: No periodic structure whatsoever.
Examples of amorphous solids include what?
A: Glass, wax, and many plastics.
By volume and weight, the largest concentrations of
crystals in the Earth are part of its what?
A: Solid bedrock.
As of 1999, the world's largest known naturally
occurring crystal is what?
A: A crystal of beryl from Malakialina, Madagascar, 18 m (59 ft) long and 3.5 m (11 ft) in diameter and weighing 380,000 kg (840,000 lb).
Some crystals have formed by magmatic and metamorphic
processes, giving origin to what?
A: Large masses of crystalline rock.
Most igneous rocks are formed from molten magma and the
degree of crystallization depends on what?
A: Primarily on the conditions under which they solidified.
What is polymorphism?
A: The ability of a solid to exist in more than one crystal form.
For pure chemical elements, polymorphism is known as
For example, diamond and graphite are two crystalline
forms of what?
Polymorphs may have wildly different what?
For example, diamond is among the hardest substances
known, while graphite is what?
A: So soft that it is used as a lubricant.
An ideal crystal has every atom in a what?
A: A perfect, exactly repeating pattern.
However most crystalline materials have a variety of
crystallographic defects, places where the crystal's pattern is what?
In semiconductors, a special type of impurity, called a
dopant, drastically changes the crystal's what?
A: Electrical properties.