Polarized light microscopy is a contrast-enhancing technique that may be utilized for both quantitative and qualitative analysis of optically anisotropic specimens. In order for polarized light microscopes to reveal details that are poorly observed using traditional microscopy techniques, they must be equipped with a polarizer positioned in the light path before the specimen and an analyzer in the optical pathway between the observation tubes or camera port and the objective rear aperture. It is then the interaction of plane-polarized light with a birefringent specimen that results in image contrast. More specifically, this interaction produces two individual wave components with different velocities that fluctuate with the propagation direction through the specimen and that are each polarized in mutually perpendicular planes. When the light components pass through the specimen, they undergo phase alterations, but are eventually recombined with constructive and destructive interference when they pass through the analyzer.
Chemical Crystals
Chemical compounds can exist in three basic phases: gaseous, liquid, or solid. In gaseous form, chemicals are comprised of weakly bonded atoms that are able to expand to fill any available space. Liquids, however, are slightly more structured than gases, the component parts that comprise them moving freely among themselves, but tending not to disperse and separate from one another. Solid compounds, which exhibit strong atomic bonding, are the most structured type of chemicals, featuring a rigid shape and a definite volume. Furthermore, many solids exist naturally as crystals, their atoms displaying distinct three-dimensional geometrical patterns. Advances in science and technology have also made it possible to create a tremendous array of artificial crystals in the laboratory, a feat that has many important commercial and industrial applications
Acetaminophen
Ampicillin
Anthranilic Acid
Atropine
AZT
Benzeneboronic Acid
Beta-Carotene
Biotin
Caffeine
Chloroisatin
Cholesterol
Clozaril
DDC
DDI
DDT
Dimethoxyhydroxycinnamic
Ephedrine
Erythromycin
Estrone
Folic Acid
Glutamic Acid
Glutaric Acid
Liquid Crystalline DNA
Malonic Acid
Miconazole
Mycostatin
Naphthaleneboronic
Nicotine
Nicotinic Acid
Pantothenic Acid
PABA
Progesterone
Retinoic Acid
Riboflavin
Succinimide
Tacrine
Taxol
Testosterone
Chemical Crystal
Urea
Uridine
Viagra
Vitamin B6
Vitamin B12
Vitamin C
Vitamin D
Vitamin E
Vitamin K3
Fibers
Natural fibers may be derived from many sources, including animals, vegetables, and minerals. The use of such fibers extends back beyond recorded history, archaeological evidence indicating that wool and flax had begun being woven into fabrics by the sixth century BC. Man-made fibers, however, which are fibers chemically and structurally altered to an appreciable extent during their production, were not developed until after the Industrial Revolution. The earliest of these fibers, including rayon and acetate, were comprised of the same cellulose polymers found in many natural fibers, though in a drastically modified form. Later man-made fibers, such as nylon and polypropylene, were created through purely artificial means and came to be classed in a separate category of fibers known as synthetics.
Acetate Fibers
Silk Fiber
Cotton Fibers
Cuprammonium
Flax Fibers
Hemp Fibers
Kenaf Bast
Milkweed Fibers
Nylon Fibers
Orlon Fibers
Polybenzimidazole 
Polypropylene
Ramie Fiber
Saran Fiber
Short Asbestos
Silver Cotton
Silver Ramie
Spectra 1000
Tencel Fibers
Thrown Raw Silk
Wild Silk Fibers
Hairs
Hair is a characteristic attribute of mammals. The primary purpose of the epidermal outgrowth is to provide insulation from the cold. Thus, animals inhabiting colder climes typically are covered in thicker masses of hair, often referred to as a coat or wool, than those native to warmer regions. Humans, who have little need for extra protection from the cold due to the development of clothing, are among the least hairy mammals. Indeed, humans have been intricately involved in increasing the hair growth of certain other animals in order to make them more productive contributors to the fur and textiles industries, further decreasing the necessity of human hair. Through selective breeding efforts, the output and quality of hair produced by sheep, goats, rabbits, and a wide array of other animals has been drastically improved for human purposes.
Alaskan Seal
Alpaca
Angora Goat Hair
Angora Rabbit Wool
Antelope Hair
Baby Caracul Hair
Badger Hair
Bat Hair
Beaver Hair
Camel Down
Cashmere
Cat Hair
Chinchilla Hair
Chinese Gray Kid
Chipmunk Hair
Civet Hair
Cow Hair
Deer Hair
Dog Hair
Elk Hair
Ermine Hair
Goat Hair
Groundhog Hair
Guinea Pig Hair
Horse Hair
Human Hair
Japanese Pony Belly
Kolinsky Hair
Leopard Hair
Lincoln Sheep
Llama Hair
Marmot Hair
Merino Wool
Mink Hair
Mole Hair
Monkey Hair
Mouse Hair
Mouton Lamb
Muskrat Hair
Nutria Hair
Ocelot Hair
Opossum Hair
Otter Hair
Persian Lamb
Rabbit Hair
Raccoon Hair
Rat Hair
Russian Cony
Sable Hair
Scoured Sheep Wool
Sheep Wool Felt
Silver Fox
Skunk Hair
Squirrel Hair
Timber Wolf Hair
Wool
Yak Down
Rocks and Minerals
Minerals are naturally occurring substances of inorganic origin that have a definite chemical composition and usually exhibit a crystalline structure. Plants and animals require a wide variety of minerals in order to survive on a daily basis. Minerals are also important, however, as the basic building blocks of rocks, which comprise the solid portion of the Earth and other planets. Rocks are formed through various means and are usually broadly categorized based on this fundamental characteristic. More precisely, igneous rocks are those that have solidified from magma, sedimentary rocks are those that have formed from fragments, or sediments, of other rocks, and metamorphic rocks are produced via the alteration of igneous or sedimentary rocks.
Actinolite Schist
Alkalic Granite
Alkalic Syenite
Amphibolite
Amygdaloidal
Anhydrite
Anorthosite
Aplite
Arenaceous Shale
Arfvedsonite Granite
Arkose
Augen Gneiss
Banded Sandstone
Barite
Basalt
Bauxite
Biotite
Biotite Hornblende
Biotite in Granite
Bituminous Coal
Bituminous Shale
Breccia Marble
Camptonite
Chalk
Chlorite Schist
Chocolate Marble
Clay Ironstone
Clay Ironstone
Coquina
Cordierite
Dacite
Diffusion Dolomite
Diopside Gneiss
Diorite
Diorite Gneiss
Dolomite Marble
Dunite
Eclogite
Ferruginous Argillite
Ferruginous Shale
Flint
Fuchsite
Gabbro
Garnet Wollastonite
Glauconite
Glaucophane Schist
Granitoid Gneiss
Granodiorite
Graphitic Marble
Gray Sandstone
Graywacke
Green Slate
Greenstone
Gypsum
Hedenbergite
Hematite
Hornblende Gneiss
Hornblende Schist
Hornblende Syenite
Ijolite
Kyanite Quartzite
Lamproite
Latite Porphyry
Lepidolite
Leucite Nepheline
Malignite
Margarite
Micaceous
Mica Schist
Micropegmatite
Monzonite
Muscovite
Mylonite
Nepheline
Norite
Novaculite
Obsidian Snowflake
Olivine Basalt
Olivine Pyroxene
Orbicular Diorite
Peperino Tuff
Peridotite
Phlogopite
Phosphorite
Pink Marble
Potosi Dolomite
Pyroxenite
Quartz Conglomerate
Quartz Monzonite
Quartz-Sericite
Quartzite Jasper
Red Sandstone
Red Slate
Rhyolite Flow
Rhyolite Porphyry
Sericite
Serpentinite
Shonkinite
Sillimanite
Soapstone
Sodalite Syenite
Staurolite Quartzite
Tactite Skarn
Talc-Tremolite
Tholeiitic Basalt
Tonalite
Trachyte Porphyry
Travertine
Tuff
Unakite
Variegated Dolomite
Verde Antique
Volcanic Ash
Volcanic Sandstone
Welded Tuff
White Marble
Miscellaneous
In addition to chemical crystals, fibers, hairs, rocks, and minerals, a number of other types of specimen may benefit from observation through polarized light microscopy. The technique, for instance, readily reveals the striations present in many fish scales and samples of human muscle tissue, as well as the structural details of fossilized dinosaur bones. Utilization of polarized light microscopy can also reveal important information regarding harmful insects and parasites that afflict humans and other animals, such as the biting louse and the whipworm.
Canine Biting Louse
Ctenoid Fish
Dinosaur Bone
Human Muscle
Human Whipworm