There's only two versions of the Freiberg and they're essentially the same, save that one has a mirror and one doesn't, with the mirror version being the preferred Freiberg by geos.
The 'Freiberger' is the original structural geology compass and was built according to the specifications of a famous geologist known as Dr. Eberhard Clar. Freiberger is the company that took the contract to make the first ever geologist's compass and they’ve been making them the same way in Germany ever since. This compass design allows a geologist to take a reading of direction and azimuth of dip at the same time.
Features:
- Permanent locking of the magnetic system - can be released during measurement by depressing the push-button and should be used for shortening the setting time
- Lockable inclinometer for inclination measurements of high accuracy
- Operates -30oC - +50oC
- Ground magnetic needle placed on edge
- Easy adjustment of the graduated circle - for each measuring technique and for setting declination values of any magnitude
- Colour coding on circle of altitude and magnetic needle (according to Clar) - unambiguous determination of the direction of dip of geological formations
- Circular spirit level for leveling, lateral glass tube for measurement at points of difficult access
- Dip measuring plate
- Horizontal level bubble for measuring where access is difficult
- Circular level bubble for simple leveling
- Dust and water resistant
Applications:
- Can be used for route surveying, for the survey of natural and artificial openings above and below ground
- Surveying of open pit or underground workings
- Transfer of geological data onto maps and plans
- Staking out of claims and sites
- General field-geological work
- Special structural-geological, deposit-tectonic, and engineering-geological rock mechanical work
- Rock work as well as moderate-accuracy surveying
Chemical Composition:
Si: 0.7-1.3
Fe: 0.50
Cu: 0.10
Mn: 0.40-1.0
Mg: 0.6-1.2
Cr: 0.25
Ni: 0
Zn: 0
Ubrige: 0.15
Ti: 0.10
Al: Balance
For other structural geology compasses, you may want to check out the following options: