C crystals evaporated from aqueous solution. Copyright
Thomas L. Webster 2004
the Crystal Slides...Nothing
could be easier to create than crystals on a microscope slide.
Two methods may be used: 1) Allowing crystals to form from
a solution and 2) melting substances between a coverslip
and a microscope slide (a "melt"). Of the 2 methods,
I prefer to allow crystals to form from solutions but not all
substances are soluble in a solvent. There is an inherent amount
of danger involved in creating "melts" and I resort
to that method as a last resort. I will first attempt to make
saturated solutions of a substance in water and alcohol, if the
substance is not water soluble.
Alcohol and some other non-aqueous solvents are highly flammable
and must not be used near open flames! It is wisest to use these
solvents in an area with adequate ventilation or use these solvents
outdoors! Exposure to the fumes of some solvents may be toxic
and some solvents are known to cause cancer! Always use extreme
caution when using non-aqueous solvents. It is highly recommended
that you wear protective clothing, gloves, a respirator, and eyewear
when performing these procedures. Never allow children to use
these solvents unsupervised!
stunning crystals may be formed by allowing saturated aqueous
solutions of substances to evaporate on the microscope slide.
The images of epsom salt crystals and vitamin c crystals on this
website are but a few examples. A small amount, approximately
1/8 teaspoon, of ascorbic acid (pure vitamin c) crystals dissolved
in about 30 ml of distilled water will form beautiful plate-like
crystals that reveal intense colors under crossed-polarized filters.
About the same amount of epsom salts dissolved in a like amount
of water will create many stunning freeform crystal structures
(see below). Spread these solutions thinly on a microscope slide
and allow the water to evaporate. Don't make the solutions too
saturated or the crystals formed will be too thick and opaque
under the microscope. It takes a little experimentation to find
the right saturation point.
substances will only dissolve in non-aqueous solvents. Some of
these solvents may be isopropyl-, ethyl-, and methyl- alcohols
or stronger solvents such as acetone and xylene. Always use these
solvents in well-ventilated areas and away from sources of open
flames and sparks (see the warning above). These caution statements
just cannot be overemphasized! It is best to dissolve the substance
in a glass container if you are using any non-aqueous solvent.
Many plastics will dissolve either partially or wholly when exposed
to non-aqueous solvents. This will not only contaminate your crystal
solution but may impose a serious health hazard, too.
crystals evaporated form a solution of ethanol. Copyright
Thomas L. Webster 2004
common across-the-counter drugs will yield photogenic crystals.
I have used acetominophen (tylenol), ibuprofin, and aspirin to
great effect. The use of a small mortar and pestle to grind the
tablets finer helps getting these substances to dissolve more
easily. Don't be afraid to "torture" the crystals as
they are forming. Subjected to different environmental conditions
crystal formations will take on different structures. Often times
I will place the microscope slide and solution in the microwave
oven and "nuke" the solution to the boiling point. This
works especially well with acetominophen (tylenol) and aspirin.
I will also place forming crystals in the freezer for a few days.
Crystal growth proceeds slowly and in many amazing directions.
Substances dissolved in flammable, non-aqueous solvents should
never be subjected to heat "torture"! This could result
in a fire or explosion and resulting burns! Never, never use flammable,
non-aqueous solvents near open flames or sources of sparks!
stated earlier, "melts" are another way to create crystals.
With this method a small amount of the substance is placed between
a microscope slide and a cover slip. The microscope slide is then
passed through a flame until the substance is melted. Once melted,
a small weight is placed on the coverslip to squeeze out excess
material and keep the material layer as this as possible. I bought
an assortment of lead fishing weights (cheaply available at any
good sporting goods store) and wrapped the weights in aluminum
foil. One or two of these weights on a coverslip is all that is
necessary to keep the material layer thin. Heat the microscope
slide, material, and coverslip "sandwich" slowly. Applying
too much heat too quickly will not only burn the material but
may cause the microscope slide to shatter. It is not unusual to
break a number of microscope slides while learning to perform
Some substances used for melts may be flammable once they are
melted! Other substances may give off toxic fumes! At a minimum,
always wear proper protective gloves, clothing, and eyewear when
performing melts! Overheated microscope slides may suddenly break
without warning! Never allow children to perform melts unsupervised!
I have taken to using a small toaster-oven for creating low-temperature
melts. Substances such as napthalene and paradichlorobenzene (both
are "moth balls") melt at low temperatures. I place
the toaster-oven outdoors to vent off any toxic fumes and the
microscope slides are safely contained within the oven. I will
slowly raise the temperature of the oven until the substance just
starts to melt. Not only does this offer some protection from
shattered microscope slides and toxic fumes but I have broken
far fewer microscope slides this way.
Never place microscope slides with non-aqueous, flammable solvents
in the toaster oven. The fumes from these solvents can heat quickly
and cause an explosion resulting in severe burns and trauma! Never
allow children to perform melts with a toaster-oven unsupervised!
Always wear protective gear when performing any kind of melt!
to Part IV...)