Diamond Collections

The DMGC diamond collection is registered under the System for Earth Sample Registration (SESAR). Sample registration is ongoing as specimens are added.

SESAR is part of the Integrated Earth Data Alliance (IEDA), hosted at the Lamont Doherty Earth Observatory of Columbia University and funded by LDEO and the National Science Foundation.  “SESAR operates a registry that distributes the International Geo Sample Number IGSN. SESAR catalogs and preserves sample metadata profiles, and provides access to the sample catalog via the Global Sample Search. 

The IGSN or International GeoSample Number is an alphanumeric code that is assigned to specimens and related sampling features such as drill holes or wells to ensure their unique identification and unambiguous referencing of data generated by the study of samples.” At this point approximately 1600 diamonds have been accessioned into the registry.

SAMPLE REQUESTS

Protocol for Sample Requests and Analysis of DMGC Deep Carbon Observatory Diamond Collection

Background

The DMGC diamond collection consists of diamonds purchased with DCO funding for the specific purposes of establishing a legacy collection of diamonds that are readily available for researcher to study, as part of a coordinated effort. Details of the samples existing in the collection can be found here.

Sample Requests

Samples may be requested by submitting a research proposal to Steve Shirey and Graham Pearson. The proposal will then be circulated to the Advisory Board who will make a decision on whether to approve the proposed use of the samples. We will use “Best Practice” guidelines recommended by the Society of Mineral Museum Professionals when considering applications. 

The collection currently contains diamonds from:
  • The Juina region, Brazil
  • Sierra Leone
  • Catoca, Angola
  • Zimbabwe 
  • Prairie Creek, USA
  • Mirny, Russia
  • Mbuji-Mayi (Miba), DRC
Proposals must contain the following information:

•    Name of Researcher
•    Affiliation
•    Project title
•    Project description, including main aims#
•    Methods to be used, specific names of laboratories and staff involved in analysis
•    Level of sample pre-characterisation required
•    Nature of sample preparation to be used and amount of sample required – no methodological testing that involves > 40% mass loss of the sample will be approved unless exceptional circumstances are demonstrated.
•    Justification for any destructive testing
•    Description of how data will be archived and an statement agreeing to send DMGC a copy of all data generated when published
•    A report on the research analysis should be sent to the collection

Other information to be included in the Project Description includes:
  • The information needed and/or sample does not already exist in the collection files.
  • The project has merit and a reasonable chance of success and completion.

  • Plans for dissemination of information in a way that benefits the research and/or public community.

    Note: – Samples should be returned to DMGC as soon as practically possible and will at all times, remain the property of the collection and the DMGC – DCO sample archive should be credited at all times.

    N.B. – Individual researchers will be responsible for adhering to correct Kimberley Process procedures for sample shipping, including filing KP documents with the relevant authorities.

Analytical Protocols:
  • Researchers must adhere as closely as possible to the recommended analytical protocols outlined below:
  • Individual researchers must pay the cost of diamond plates being made and we will supply recommendations for where this work is done. 
  • All diamonds to be analyzed must be initially characterized by FTIR spectroscopy and cathodoluminscence and the data deposited with DMGC, prior to the start of more destructive analytical work.
An idealized flow of analytical work would be:
  • FTIR spectroscopy to determine nitrogen content and aggregation levels across the plate. If no plate is made it is essential to attempt to obtain a spectrum from a suitable portion of the stone
  • Raman spectroscopy or X-ray determination of any inclusions
  • Cutting and polishing of plates or “windows” from agreed portions of diamonds (where practical)
  • Additional Raman/Xray work
  • Cathodoluminscence imaging of the diamond plate to image internal structure
  • EMPA analyses of inclusions or fluids

  • Carbon isotopic measurement by ion microprobe

  • More destructive analyses (e.g., laser ablation or cracking of plate to recover diamonds).

    All remaining sample materials following analysis are to be returned for storage at DTM Carnegie, where the collection is held.

DMGC Advisory Board for Sample Requests:
  • Graham Pearson (University of Alberta)
  • Steve Shirey (Carnegie Institution for Science)
  • Erik Hauri (Carnegie Institution for Science)
  • Emilie Thomassot (University of Lorainne, France)
  • Fabrizio Nestola (University of Padua)

DATABASE

The establishment of a database of diamond data, called “DiamondDB” from the literature has been initiated.

A special diamond-specific data template has been created that will allow for the unique data types that diamond researchers collect. It is not yet operational but data from the following papers have been input.

When operational, DiamondDB will function like its siblings PetDB, SedDB, and NavDat. These databases are part of EarthChem which, like SESAR is hosted at LDEO.

Diamond Database

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