The GMZ 171
The GM171 is a high-end stereo microscope designed to meet the needs of jewellers and all users involved in the examination of gemstones. The necessary visual magnification is achieved by the optics of the established SMZ171 stereo microscope, available in a binocular version or with a photo output for digital documentation. The 1:6.7 zoom provides a total magnification of 50x with a resolution of 240 line pairs per mm in standard optical configuration. Close-up lenses increase this to 480 lp/mm. The working distance of 110 mm guarantees a large working distance. The field of view of 23 mm allows a quick overview. Special sample holders are required for manipulation and precise positioning of the sample. Optional eyepieces maintain the working distance but increase the total magnification. The tripod offers 30W bright field/dark field lighting in transmitted light. In reflected light, a 7W fluorescent tube is used on a flexible gooseneck. The microscope base can be tilted (0° to 45°) to enable fatigue-free working thanks to an ergonomic sitting position. The Z-drive is individually adjustable, allowing precise and sensitive focusing even at high magnifications. The GM171 is an advanced instrument for gemmology and meets the most diverse requirements of this field of application.
Ergonomic setup for optimum functionality
The mechanics of the GM171 are based on functionality and ergonomics. Elegant and robust at the same time, this microscope is ideal for everyday use. Thanks to the variable viewing angle, the GM171 enables fatigue-free working. The optics can be tilted for an individual seating position (0° = upright, up to 45° inclined view), and the tripod base can be rotated 360° to allow access for a second observer. The eye relief is adjustable from 52-75 mm, and the diopter adjustment on both eyepieces offers the best compensation for individual visual impairments and perfect use of reticles.
Improved optics for better quality
The optics of the SMZ171 provide improved detail information for all types of gemstones. In the basic configuration, the 10x eyepieces work perfectly with the zoom body factor of 0.75X - 5X. Visual impairments can be compensated for by a +/- 5 dpt diopter adjustment on the eyepieces themselves. Attachment lenses up to 2X double the total magnification to a resolution of 480lp/mm, but reduce the working distance. The eyepieces with up to 20X magnification keep the working distance of the basic equipment (110mm) constant.
Effective and flexible lighting
As with any other stereo microscope, the GM171 requires lighting that is perfectly suited to the characteristics of the samples. Transparent gemstones certainly require more than standard transmitted light. In addition to a 30W halogen bright field, the GM171 also provides a transmitted light dark field with variable iris diaphragm for clear viewing of inclusions or edges. The 7W fluorescent tube with 6400K colour temperature (daylight) in the incident light is important for assessing the colour of a stone. At the same time, this "soft" light reduces reflections that are visually distracting or interfere with image documentation. The gooseneck mount of the incident light allows the best image results by freely selecting the illumination angle.
Useful things with a big impact
In order to achieve the best possible results, a stereo microscope for gemmology requires a range of accessories that are tailored to the characteristics of the samples: weak colouration, +/- transparent, highly reflective surfaces with incident light illumination. A range of stone holders allow precise positioning of the samples for reflected and transmitted light. A polarisation set (polariser, analyser) is required for detecting birefringence. An optional diffuser reduces reflections from the sample surface. The immersion chamber helps to estimate the refractive index and provides information about the material. The "proportions" eyepiece is an aid for checking the dimensions of a stone: upper part, girdle, lower part. A special diamond holder helps with optimal positioning.
GM-171, trino, 7.5-50x, wd 110mm
Head: Trinocular
Optical system Greenough
Inclination 45º inclined
Interpupillary distance 52-75mm
Diopter adjustment On both eyepieces, +/- 5 diopter
Eyepieces Widefield WF10X/23mm
Objectives system Zoom, ratio 6.7:1
Objectives 0.75X~5X
Working distance 110mm
Stand type 360º rotary base
Diaphragm Iris diaphragm, adjustable aperture Ø41mm - Ø2mm
Head holder For Ø76mm head
Focus mechanism Coarse focusing system with tension adjustment
Focusing stroke 125mm
Incident illumination Fluorescent 7W with Gooseneck adjustable
Transmitted illumination Quartz Halogen 6V/30W with intensity control
Illumination features Darkfield illuminator
Transformer Internal
Power supply 100-240V (CE)
Accessories included Dust cover, stainless steel wire stone holder, aluminium carrying case
Dimensions LxWxH 391x236x505mm
Base 306x236mm
Column/Arm Height 268mm, 45º tilting arm
Net weight 8.2kg
