THE
Microscope
and
Photomicroscopy
A CLOSER LOOK
THE IMPORTANCE OF A MICROSCOPE
The Microscope allows us to see inside minerals. It is imperative that your Microscope have quality optics; they provide a crisp, clear view. The sharper your images, the more evident things appear. The Microscope is primary to all instruments.
Photomicroscopy is the art and science of capturing images on a microscopic level. This allows us to retrieve evidence in order to identify a gem and has proven successful in most cases.
It is extremely important to look through the entire gemstone, note any evidence as to its identity, and record it for further examination. Taking digital pictures makes it easier to communicate identification with others as well.
LIGHT SOURCES
The use of various lighting applications will help discover the inside of a stone. Besides Polarized and Diffused Lighting Techniques, three key sources are seen here.
● Darkfield | Brightfield lighting: The light radiating from the well of the microscope helping to light up the gemstone from underneath.
● Overhead lighting: The daylight lamp fixture extending from the Stage use reflected light to identify polish, graining, color zoning, and other characteristics of a stone.
● Fiber Optic lighting: Fiber Optic lighting is directed at the gem from different angles. It is very bright and exposes many inclusions that are difficult to see.
OBJECTIVE LENS
The Objective Lens is located at the bottom of the nose piece. It is the first high-powered integrated lens that gathers light from a gemstone specimen.
It relays the image to the Eyepieces through channels.
Special lenses can be applied to the Objective Lens for greater magnification. Increased magnification on this lens leaves less working space for examining a stone.
Unlike microscope slides for medical specimens, gemstones need extra working space to be examined properly because of their size and needed rotation.
OCULAR LENS | EYEPIECES
The ocular lens, or eyepiece, is also an optical assembly rather than a single lens. It is less complicated than the Objective lens.
Eyepieces define a microscope's field of view. They work in line with the Objective Lens. High quality lenses deliver outstanding magnification.
By incorporating a digital camera within an Eyepiece chamber, a gemologist can capture specifics images. These images provide critical
evidence to Gemstone Origin and Identity.
Recognizable treatments, synthetic growth processes, and simulated gemstones can also be detected using a combination of techniques.
PHOTOMICROSCOPY
ART FROM ANOTHER WORLD
gemstone microscopic imaging
The nature of these two inclusions can be detrimental to the diamond.
The inclusion is also obvious to the naked eye.
This Diamond would typically be called an I1 by most sellers because most do not understand how inclusions can affect a Diamond's integrity,
In this case, the Diamond can be cleaved, or broken in two parts, if struck on something hard enough.
Hardness is not to be mixed up with the durability of a Diamond. Those are two separate attributes.
Some inclusions commonly found in Emeralds are crystals, fractures, needles, fingerprints, growth tubes, liquid inclusions, and one- two- or three-phase inclusions.
Here we can see a collection of all these inclusions together in this moderately included Emerald.
Phase one, or liquid pockets in the Emerald are quite common.
Phase two Emerald inclusions contain a gas bubble within the liquid pocket.
Phase three inclusions contain a crystal like structure within the liquid pocket along with a gas bubble.
These Three Phase inclusions are frequently seen in Colombian Emeralds.
Recap:
Phase I - a pocket of liquid in the Emerald
Phase II - a pocket of liquid with a small gas bubble trapped inside.
Phase III - A crystal (small square) seen with a gas bubble trapped in the liquid pocket,
According to GIA, color zoning is seen as areas of different colors caused by variations in growth formation.
The color zoning here is depicted as strong Blue angular streaks throughout the stone.
This image is under high magnification and these saturated areas of color do not typically stand out to the naked eye.
Sometimes, gemstones are cut to enhance these features, or even enhance the color of a stone.
This is an early Brilliant Cut Diamond.
Note the slightly off-round shape because the girdles were bruted together while shaping the diamond.
This cut also contains a much smaller table; producing more fire than usual.
Peering through the center of the table is the culet. Culets are noticeable on Old Euro Cuts. At the time culets were faceted to avoid chipping or breaking off the tip of the stone.
Hence, many sellers refer to glass as crystal, which is correct.
It is a crystal, but because there are different types of crystals, this confuses many people.
This image shows a perfectly round Gas Bubble. This is normally a sign of glass.
Glass is soft. It is prone to chipping and breaking.
In addition, glass gemstones are manufactured in molds. The rounded facet junctions and pits seen are characteristic of the mold the glass gem was made from.
The Opal pictured here contains "Harlequin" (rectangular brush strokes) and "Pinfire" (minute patches and specks) patterns. These Play-of-Color patterns make every Opal unique.
Opal, for the most part, is translucent (unless it contains part of it's host rock.)
This image depicts the Opal in darkfield lighting. You can see the network of very small fissures where water evaporated, leaving the silica and drying out the mineral.
The image where Opal's pattern is seen is overhead lighting.
At first glance under the microscope, this wavy feather looks like a piece of lint because it is just below the table.
Inclusions like these will help to identify your gemstone better than a laser inscription that can be polished off without carat weight loss.
The flash of color exposes the filler in bright orangy-yellow colors. A purplish-pink color was seen as well but not captured.
