M2S Terminology

These terms, and the language used to talk about MAP on this website, are not rigorously defined for scientific precision. They are intended to help non-scientists understand what MAP does. Please note that this list of terms will grow with time, and some definitions will change in detail as usage changes. Should you desire a more technical discussion of our coined terminology please contact our research staff at .(JavaScript must be enabled to view this email address).
Alluvium

Significant because it can contain concentrations of valuable ore minerals such as gold and platinum and gemstones such as sapphires and diamonds, it is any loose soil or sediment not cemented together.

Beryl

A silicate mineral; gem variety of this mineral include: aquamarine (blue), emerald (green), heliodor (yellow), and others.

Cassiterite

A mineral which is a key source of tin.

Channels (in the spectroscope)

Light emitted from the plasma is collected by the spectrometer. Amplitudes of energy at different wavelengths in that light are recorded  across a spectrum. The number of separate wavelengths recorded in that chosen spectrum varies, depending on the instrument in use. In fact, the system does not usually separate out pure, single wavelengths, but records energy in narrow bands… channels… of frequencies. Most of Materialytics developmental work has used a spectrometer that distinguishes thousands of channels of data in the bandwidth. 

Coltan

A combination of the minerals columbite and tantalite, hence col-tan, these two minerals are commonly found together and are key sources of niobium and tantalum respectively.

Corundum

An aluminum oxide; gem varieties of this mineral include ruby (red) and sapphire, which includes any color other than red.  

Digital Signature

See  Quantagenetics® Signature.

False positive/ false negative

When the system asks ''does this unknown sample match Reference X,'' and the answer is ''no'' when there really is a match, that is referred to as a false negative. When the system answers that there is a match when there really isn’t, that is referred to as a false positive.

We rate the accuracy of M2S® by subtracting the combined number of false negatives and false positives from the total number of comparisons the system made of unknown samples against the Reference Database. For example, if we test three hundred unknowns against a database containing, say, 4000 reference samples, and we get two false positives and three false negatives, we calculate the accuracy by subtracting 5 from 300, then calculate what percentage 295 is of 300: 98.333%. The average accuracy of all the material tests we have run to date is currently in that range. Accuracy improves as the Reference Database grows larger. M2S will produce higher accuracy with a database of 8000 than with 4000.

Fingerprint

See Spectrum.

Laser-Induced Breakdown Spectroscopy (LIBS)

See Plasma Spectroscopy

Matrix

Minerals (gems) are not always found as separate lumps of stone. The gemological material is usually formed inside other rock, referred to as ''matrix,'' which often must be chipped away to release the more valuable gem.  Many of the samples in our collection are tested while still partially in matrix, and the matrix itself is often analyzed to help establish the Quantagenetics® Signature of the samples.

Model

A model is a description of a system using mathematical/scientific concepts. Models can take many forms but most models are based on determining in advance what to keep and what to ignore. All models require redevelopment when a new material (e.g.. from a different country) is added. M2S® does not use models.

Optical Emission Spectroscopy (OES)

A method for analyzing materials, in which enough energy is put into a tiny amount of the sample to convert it to the form of a plasma, which emits light as it cools. Because each element in the periodic table emits light at a different wavelength (or more than one wavelength), it is possible for an instrument to identify the contents of the plasma by determining which wavelengths are present in the light from the plasma. There are several methods of producing the plasma.

Organic Materials

In chemistry, organic materials are those based on carbon.  We don’t use the term strictly, but refer to any material derived from living things…plants, bacteria, cattle…as organic. In the USDA sense of the term, in time we plan to analyze certified organic and non-organic material of the same type to determine differences.

Plasma

Matter ordinarily occurs in the form of a solid, a liquid, or a gas. When enough energy is pumped into any of these materials, a very energetic, active bubble of ionized material forms, called a ''plasma''. Plasmas are not rare or exotic. The light from a fluorescent bulb and from lightning is produced by a plasma.

Provenance

The place of origin of the material being examined…e.g.  the mine a gem came from or the place an organic sample grew.

Quantagenetics Sequence

A Quantagenetics® Sequence is a collection of spectra (any number from two up) from a series of laser shots on a sample. Those shots, typically 30 or more, are made at different points on the sample to compensate for variation in the sample material. The Quantagenetics Sequence characterizes the sample, and is used in comparing one sample with another.

Quantagenetics Signature

A Quantagenetics® Signature represents the character of samples from a definable source.  It is the cluster of sequences of samples that have something meaningful in common.

 

One example would be products from a single manufacturer.
Another would be gems from a particular mine, or country, or region.
Another might be fruit from a particular orchard or district.

 

Quantagenetics Signatures are the groupings of known samples with which we can compare unknown samples. Materials that were formed under the same conditions, of the same elements, have similar Quantagenetics Signatures. In the case of apples and oranges, to pick a familiar example of things to compare, their Quantagenetics Signatures are determined by the nature of the soil in which they grew, fertilizers, pesticides, rainfall, temperature, and the rest. The Quantagenetics Signature of emeralds from mines in a particular deposit in Afghanistan is different from that of emeralds from a deposit in Colombia. In practice, the Quantagenetics Signatures of stones from one valley in any region are detectably different from those of stones from the next valley over.

 

Quantagenetics Signatures are determined by everything in the genesis of the materials under examination.  That genesis may be natural or artificial…in the earth or in a factory. The composition of a sample is affected by trace elements available when it was being formed, the changes in temperature and pressure at which it was formed, the rate at which it cooled, weathering, the passage of time, and all other factors, known or unknown.

Reference Collection

In our usage, the Reference Collection is the physical collection of well-identified and documented samples of materials against which we will compare unknown samples, looking for matches.  The term refers to all of the physical samples, both analyzed and not yet analyzed.

Reference Database

In our usage, the Reference Database is the whole collection of Quantagenetics® Sequences obtained from the samples in the Reference Collection of materials that have been analyzed, and stored in digital computer memory.

Sample

A ''sample'' refers to any piece of material to be tested; including, but not limited to, manufactured parts, geological materials and organic materials.

Sample Database

Just a less formal term for a Reference Database.

Spectrum

Previously referred to as a "fingerprint," Materialytics has determined that "spectrum" is a better descriptor of the data produced in a single laser shot on a sample. A graph of the data indicates the intensity (amplitude of energy) at each wavelength on the spectrum detected by the spectrometer in our system. That is the spectrum of the sample.

Stage

In our usage, this refers to a “microscope stage,” which is the platform on which a sample sits in the test chamber under the laser. Our custom stage moves in very small increments in X, Y, and Z axes under digital control.

Statistically Significant

Statistics deals with averages and probabilities. To calculate statistics that are meaningful, it is necessary to use a large number of data points. If you have just five data points, a single anomaly will give you an error of 20%...not useful. If you have ten data points, the error is 10%...if twenty, then 5%.  Traditionally statisticians want a bare minimum of 30 data points to work with before they consider results of calculations ''significant.''  We always include a bare minimum of 30 fingerprints from laser shots to create a Quantagenetics® Sequence of a sample, and we collect a bare minimum of 30 samples from each site to establish a Quantagenetic Signature that is statistically significant.

Tourmaline

A complex silicate mineral commonly zoned and found in numerous colors.

Trace Elements

Geological samples are almost never pure. Diamond, for example, is usually defined in high school textbooks as a form of ''pure carbon,'' but natural diamonds and other gems contain small traces of other elements. Such trace elements may affect the color or other characteristics of the stones.  M2S® does not look for specific elements…primary or trace…though it may be possible to determine the geochemistry of samples by examining the data we collect.

Traces of Analysis

When a laser converts a small amount of material to a plasma, the process leaves a mark. That’s unimportant in the case of samples such as road-surfacing materials, but when a finished gem is being examined, people are concerned about these traces of testing. In practice, the traces our system leaves are not visible to the naked eye. Jewelers can find them when they hunt for them, using magnifying loupes, but they are trivial.  In comparison, the traces of testing that our system leaves is no bigger than that of the commonly used LA-ICP-MS test instruments.

Wolframite

A mineral which is a key source of tungsten.