G-Probe Previous Rounds

G-Probe Previous Rounds

Reports for G-Probe rounds 1 and 2 were based on the format adopted for the GeoPT programme at that time, with tabulations of z-scores as a means of performance assessment.

In contrast, the legacy reports for round 5 onwards contain simple tabulations of the data reported by participating laboratories with multi-coloured diagrams showing the distribution of data by technique. They do not contain z-scores nor any other assessment of the quality of the data. Moreover, the “assigned values” do not have the same meaning as defined in the GeoPT protocol. For G-Probe these target values were obtained from one or two laboratories and are different from the median values of all participants.

From round 23 onwards, the operation of G-Probe has been harmonised with that of the GeoPT programme, with an online web interface for data reporting, the use of robust statistics to derive consensus values and individual z-scores issued. More details are available at www.gprobe.info

Round Year Material Epoxy colour Name Report Link
1 2001 basalt glass TB-1G GGR 26, 197-235
2 2004 nephelinite glass no colour NKT-1G (GeoPT29) GP-2 report
3 2007 diorite glass no report
4 2009 synthetic CaCO3 powder pellet MACS-3 no report
5 2010 basalt glass BBM-1 GP-5 report
6 2010 basalt glass pink BNV-1G  (GeoPT16) GP-6 report
7 2011 basalt glass (MORB) no colour BEND-1G GP-7 report
8 2011 spiked soda lime glass dark blue GSE-1 GP-8 report
9 2012 andesite glass AGV-2G GP-9 report
10 2012 synthetic apatite powder pellet MAPS-4 GP-10 report
11 2013 diabase glass white DVA-1G (W-2G) GP-11 report
12 2013 gabbro glass GSM-1G GP-12 report
13 2014 diabase glass light grey GP-DB (DNC-1G) GP-13 report
14 2015 basalt glass greenish-yellow BBRZ-1G (BRP-1G) (GeoPT25) GP-14 report
15 2015 syenite glass light purple SyMP-1G (GeoPT39) GP-15 report
16 2016 basalt glass (MORB) no colour BSWIR-1 GP-16 report
17 2016 basalt glass green-yellow Gab-JPN (JGb-1) GP-17 report
18 2017 dolerite glass milky light green TazDol-1G GP-18 report
19 2017 gabrro glass light orange OU-7G (GeoPT38) GP-19 report
20 2018 spiked basalt glass (TE at ~50 ppm) milky light blue SynB-2G (GSD-2G) GP-20 report
21 2018 spiked basalt glass (TE at ~500 ppm) milky blue SynB-G3 (GSE-2G) GP-21 report
22 2019 spiked basalt glass (TE at ~3-5 ppm) milky white SynB-1G (GSC-2G) GP-22 report


“Year” is the year the sample was distributed. The epoxy mounts for most rounds were given a unique colour to aid identification. Where the powdered form of a material was also distributed as part of the GeoPT scheme the relevant round number is given.  Where no information is available, this is indicated by “-“.