Mineral Separation Facilities


The Department of Earth Sciences has a variety of equipment available for preparation of samples for study. This page shows an overview of the available labs and equipment. The labs are shared among different groups and are thus managed by the group responsible. The person-in-charge is listed with the equipment and/or lab in question. 

Rock Disaggregation

Rock crushers

NO CO 13 – Contact Lydia Zehnder or Clara Onken

The rock crushing room is equipped with a hammer and anvil, jaw crusher, a vertical mill, a hydraulic press, and a variety of powder mills (agate & ceramic, tungsten carbide, and steel). This allows for disaggregation of large and small samples, and generation of powders for various geochemical analyses.


NO CO 17.1 – contact Giuditta Fellin or Rebecca Zech

selFrag stands for Selective Fragmentation, a method wherein high-voltage (HV) discharges are applied to disaggregate solids. Fractures generated are generally along grain boundaries, allowing excellent preservation of phases of interest. The machine also has semiautomatic programming, allowing for easier and faster processing of samples. Sieves are provided in the room for wet sieving after fragmentation, and an oven for drying samples.

Mineral Separation

All labs listed in this section are managed by Dr.Giuditta FellinFor users affiliated with the SGT group, please contact Ana Lorena Abila.

Wilfley table

NO CO 17.1

The Wilfley table uses a method of density separation using running water. Grains of <500 um are slowly dropped into a tilted, vibrating table with multiple ledges running parallel its long edge. The vibration and tilt, in combination with running water across the table, separates the grains according to their density, with lighter grains transported by the water across the ledges (i.e. perpendicular to the ledge), while denser grains travel along the ledges (i.e. parallel to the ledges). 

Magnetic separators and manual sieves

NW D 75.1; NW D 79.1

A variety of magnetic separators and sieves are available in the department. Sieves with mesh size 2 mm to 63 um are available for manual use. Four magnetic separators are also available, which allows for separation of minerals based on their magnetic susceptibility. The different magnetic separators allow for separation of minerals with very different susceptibilities (i.e. quartz from garnet) or those with similar susceptibilities (i.e. quartz from feldspar). 

Heavy liquid separation

NW D 79.1

Heavy liquid separation employs the use of heavy liquids to separate minerals based on their density. Various heavy liquids are available in the lab, i.e. bromoform (2.88 – 2.89 g/cm3), methylene iodide (3.33 g/cm3), and Clerici solution (4.03 – 4.04 g/cm3). This lab is also equipped with a magnetic separator and an oven.

Stereoscopes and picking microscopes

NW D 79.1; NW F 74

For studies requiring specific mineral phases (e.g. zircon and apatite thermochronology), microscopes are available in the D and F floors. These are equipped with both plane polars and crossed polars and can be attached to computers for photographing and measuring grains.

Thin Section Preparation

Rock Saw

NO B 69.4 – 69.5

For users affiliated with the Geological Institute, please contact Emily Hinshaw.

There are two available rock saws in the department. Further information can be found here (requires ETH log-in).

Preparation Labs

Thin sections for use under optical microscopes, scanning electron microscopes, and electron microprobe can be produced in these labs. Various smaller rock cutters, polishers, and related equipment (i.e. weighing scales, grain mounts, hot plates, etc.) are available for use.

For users affiliated with the SGT group, please contact Remy Lüchinger.

Examples of rock cutters in the lab.
Other equipment in the preparation labs.
Various rock polishers at different grits are available to use.