GEMOLOGICAL BASE
1. Posture comfort is important issue to professional gemologist who spends long periods of time using the microscope. Thus, the gemological system must be ergonomically made and cleverly designed with every detail taken into consideration for optimum performance. The microscope stage housing the optics, dark field and other parts, should preferably incline and rotate to its base, adjusted to the most comfortable position. Microscope pod inclination is important for easy manipulation, but eventually the incline mechanism wears out. Gemlab is using a manual lock mechanism that secures the inclination at all times. Currently in all gemological microscopes the wrist manipulating the gemstone is situated about 170mm high from the desk top, literally "hanged" in the air or resting on the microscope stage, which eventually gets very hot. Gemlab's ergonomic design allows optimum comfortable wrist and hand positioning because the hand is resting on the desk top while manipulating the gemstone not exceeding 75mm high.

2. Lighting, lighting control, and related functions are of paramount importance. The gemological microscope base houses the lighting system and provides the following lighting environments:

Dark field illumination. The dark-field illumination system allows the inclusions in the gem to be observed against a "dark" background. The dark field effect may be achieved using tungsten halogen lamp, but it becomes hot, often exceeding 50 degrees C, impossible to work continuously for more than an hour. Tungsten halogen lamps have color temperature below 3300 degrees Kelvin. Nearly all microscopes in the market use a dimmer to control the light intensity; thus, a yellow tinge is produced because the color temperature is lowered. To avoid the yellow color nearly all microscopes in the market use an iris diaphragm where its aperture "controls" the light intensity while maintaining the color temperature; however, the angle of the light is changed, thus the dark field effect is not fully achieved. Microscopes sold by Gem Instruments use a tungsten halogen lamp, still producing the yellowish tinge and heat. Microscopes sold by Eickhorst use special discharge virtually heatless lamp, with color temperature of 6000 degrees Kelvin and solving the problem satisfactory. Gemlab's LEDscope uses a series of ultrahigh intensity LEDs providing a superb heatless lighting environment without spike and flicker irregularities having constant color temperature over 5500 degrees Kelvin and CRI (color rendering index over 90) with dimmer having linear light intensity control without producing yellowish tinge.

Overhead illumination. Reflected light is mandatory feature suitable for examining clarity, finishing grade, color differential, and surface imperfections in diamonds and colored gems. Fluorescent lamps, LED lamps, tungsten halogen lamps may be used as overhead illumination.

Incident condensed point illumination is important when specific spots are to be illuminated for detail observations of inclusions in gems. Nearly all gemological microscopes in the market use a self-supported fiber optic light guide aiming the specimen. The light produced from a tungsten lamp which is primarily used for dark field illumination, eventually becomes very hot and it does not provide proper illumination; in my view this type of incident light is useless.

Gemlab, Eickhorst and others use self-supported, incident LED light plugged into a standard USB port. Gemlab uses an L-shape fiber-optic pipette attached to the LED light producing increased and concentrated heatless light to a specific spot, thus improving greatly the incident illumination. Gemlab's exclusive design houses all electronics and power supply in digital circuitry boards delivering electrically noise-free lighting environments.

Ultraviolet long wave light (365nm). Ultraviolet fluorescence illumination is necessary to observe fluorescence in diamond color grading and surface characteristics in gemstones. This feature is absent in all gemological microscopes (except HRD). Gemlab uses 16 ultrahigh intensity 5500 degrees Kelvin LED lights providing oblique white light, or 16 LEDs high intensity producing ultraviolet long wave light at 390 nm. The dual illumination is controlled with a dimmer and it is attached to the microscope stage with an adjustable holder.

3. Gem holder. A wire gemstone holder is desirable that allows observation of the stone without the risk of flying out of the tongs. Gemlab uses wire tweezers with magnetic ball mounted left on right post for greater maneuverability of the specimen. Flush-mount tweezers are also available. There are several types of gem holders in the market.

4. Bells and whistles. In my opinion, bells and whistles, like the light intensity displayed in digital LCD readout and memory recall -equipped in the GIA microscopes- serve no real purpose. It just increases the cost for marketing reasons. In the overhead illumination, Gemlab uses a pilot indicator with dual-purpose colored lamp (green for white light, red for ultraviolet illumination) dimmed proportionally according to their light intensity.

5. Microphotograpy. There are several companies selling various apparatuses for taking microphotographs. Most of them are not suitable for gem microphotgraphy. Here are the comments of one of my students:
" I purchased myself a digital "live feed" camera for my microscope at home. I am wanting to catalogue stones that I have in my collection -all of which have been purchased for their inclusions. The project was a failure. The camera that I purchased is not appropriate for gemstone microphotography. I purchased it from an American on line store, and it was sold as the best accompaniment to their gem microscope that I already own. However, my experiences have been disappointing and the company has confirmed that as I increase the magnification I loose depth ofvfield. The image quality is therefore flat and grainy. In addition to this the colour is not representative of the actual object. There is a time delay from the microscope to the computer monitor that is so exaggerated, it makes continual movement and rotation of the stone impossible, and as the camera sits on a trinocular port, the image does not directly correspond to the one viewed through the eyepieces. The company has offered a refund, and suggested an adaptor for use with standard digital or analogue camera."

SAFETY. Generally, no accidents or injuries are reported due to malfunction of the gemological microscopes. However, there have been serious concerns on some models of gemological microscopes marketed by certain manufacturer where live electricity is exposed on unprotected 110Vac electrical outlets fixed vertically on the gemological base: spilling water, or touching with tweezers these plugs may cause serious accidents.