Diamond Deposition Research Articles

Early stages of polycrystalline diamond deposition: laser reflectance at substrates with growing nanodiamonds.

The chemical vapor deposition of polycrystalline diamond (PCD) films is typically done on substrates seeded with diamond nanoparticles. Specular laser reflectance has been used in tandem with a continuous film model to monitor the thickness of these films during their deposition. However, approaches to gain information on properties that strongly affect film morphology, such as the areal density of seeds, remain largely unexplored. This work outlines a strategy for using laser reflectance measurements to refine the monitoring of film thickness during deposition, estimate the mean equivalent radii and the areal density of seeds, and estimate growth incubation periods. We present a general model based on the Rayleigh theory of scattering for laser reflectance at substrates with growing nanoparticles that captures the early stages of PCD deposition. We test our model experimentally by depositing diamond under identical conditions on silicon substrates with various seed densities and by comparing seed densities obtained by scanning electron microscopy to those determined by our strategy. We also explore the different deposition stages for which our model and a continuous film model can be used safely. In addition to providing guidelines for characterizing PCD deposition, this work may also advance the general understanding of nanoparticle growth and formation.

Prospects for the Use of the Silurian Carbonate Sequences of the Alakit-Markhinskiy Kimberlite Field for Drainage Water Injection

The development of the unique Yubileinaya pipe diamond deposit is accompanied by the formation of highly mineralized drainage waters, represented by practically unaltered natural brines of the Lower Ordovician and Upper Cambrian aquifers. Currently, drainage waters are injected into intrapermafrost collectors used as the main brine-absorbing structure. The lithofacies conditions of the Alakit-Markhinskoe kimberlite field has been chosen because of presence of the most representative Silurian sections in Western Yakutia, overlain by members of Carboniferous and Permian terrigenous deposits, as well as fairly thick trapp effusive fields (50–150 m). The study of cryohydrogeological conditions in the carbonate and terrigenous-carbonate rocks of the Silurian was carried out in the period 2014-2022 using standard methods to assess their potential for intrapermafrost reservoirs formation. In result of the studies, the main lithological types of the Silurian rocks, which are capable of forming an intrapermafrost technogenic aquifer due to the injection of drainage water and providing the safe development of the deposit to the entire design depth, are described.

Methods and Test Benches for Cutting Tools Testing—A Review

Mechanical mining is a widely used method of separating materials from the face to obtain a useful mineral (e.g., coal, metal ores, salts, and diamonds), to make underground workings (e.g., mine galleries, tunnels, and underground garages), level roads, shape slopes, or to dig ditches. Mechanical mining is applied in the mining branch, tunnelling, road, and construction industries. Depending on the mechanical properties of the rocks, most frequently described by uniaxial compression strength, various machines and tools are used. The methods of mining high-strength abrasive rocks that have been used and developed in recent years are particularly applicable to the mining of copper, gold, tungsten, platinum ores, diamond deposits, and tunnelling. In addition to rock strength, the effectiveness of the mining process is affected by abrasiveness, which influences the rate of abrasive tool wear. Therefore, in various research and development centres, but also in production companies, tools are tested on unique stands. Tests are carried out to determine the cutting resistance and assess the wear rate. This article reviews methods and benches for testing mining tools, conical picks, and discs. Various solutions for testing single tools and cutting heads have been presented. The analysis conducted has revealed that despite the large number and great diversity of different test benches, there are no appropriate methods and stands for testing the wear rate of materials intended for mining tools.

Влияние экологической ситуации бассейна реки Вилюй Якутии на показатели качества рыбных ресурсов

The article considers the quality indicators of fish resources extracted in the basin of the Vilyu river of the Nyurbinsky district of Yakutia, which is a zone of industrial development of a diamond deposit. The influence of the environment on the safety of various species of fish that make up the fauna of the Vilyu River near the village of Nyurba was studied; organoleptic, physico-chemical, microbiological, parasitological studies of frozen fish specimens were carried out: pike, tugun, peled. According to the results of veterinary and sanitary studies, it was found that bacteria of the Escherichia coli group were found in the tugun fish sample during microbiological examination, which indicates repeated defrosting of fish; the remaining fish samples (pike, pelage) were benign and met the requirements of regulatory documentation. Laboratory analyses conducted on organoleptic, physico-chemical, microbiological indicators, parasitological studies indicate that pollution of the Vilyu River as a result of industrial waste dumping, which occurred in 2017-2018, did not affect the quality of fish fauna. Timely financing and implementation of measures within the framework of the government program "Development of water supply systems of the Vilyui group of uluses for 2019-2024" stabilized the environmental situation in the Vilyui group of uluses. Keywords: ECOLOGY, FISH RESOURCES, EXPERTISE, SAFETY, QUALITY

Improving the pit wall seepage resistance at the V. Grib diamond deposit

Introduction. V. Grib deposit development includes complex dewatering operations, all water-bearing rocks overlying the mining floor are drained. The open pit is mainly flooded by the Padunsky aquifer system. At present, the open pit is being drained by surface dewatering wells together with mine drainage. In total about 7–8 thousand m3 /h of drainage water is pumped out. Setting of the problem. Uncovering a multilayer water-bearing strata characterized by different filtration characteristics of rocks contributes to the formation of pit walls in the Padunsky strata that have not been dewatered. The height of groundwater seepage on pit walls reaches 50 m due to the low conductivity of the Padunsky strata bottom. It is suggested that the Padunsky strata bottom should be dewatered using lateral drain holes built from the pit to the wall benches in areas with no dewatering wells. Methods of research. For pit wall stability improvement, the developed multilayer numerical model of geofiltration is applied to study the use of lateral drain holes built from the pit. The finite difference method in the GMS MODFLOW package was applied for modelling. Research results. It has been found that the operation of 12 lateral drain holes during 1 year reduces the height of groundwater seepage on pit walls by 15–20 m, contributes to the groundwater level decline of the Padunsky aquifer system by 5–10 m on the drainage contour of dewatering wells; water inflow to lateral drain holes will be 810–850 m3 /h. Conclusions. The feasibility of lateral drain holes for the Padunsky strata dewatering intensification in the adjacent rock mass has been established using the method of numerical modeling.

Statistical Features of Georadar Signals Obtained by Probing Horizontal Layered Media in Permafrost

Relevance. To study the structure and properties of rock masses in the permafrost zone, such a method of geophysics as ground penetrating radar is successfully used. The existing methods of GPR measurements make it possible to obtain large volumes of reliable data on the layered structure of permafrost rocks. The methodological support for processing and interpreting data is developed much worse. Thus, manual and semi-automatic methods are used to identify the in-phase axes of georadar signals confined to the boundaries of rock layers, which significantly slows down the process of cameral work. Existing methods for automating the selection of in-phase axes of georadar signals do not always successfully cope with this task, since the statistical characteristics of georadar traces obtained by probing a horizontally layered media are very variable. The purpose of the research is to establish the statistical features of georadar signals that form the in-phase axes obtained by probing horizontally layered media in permafrost. Research methods – statistical analysis of the results of field georadar measurements in the Anabar region of the Republic of Sakha (Yakutia) at the site of the Mayat diamond deposit (AO Almazy Anabara) using the GPR OKO ABDL-Triton. Conclusions. The research of the amplitude characteristics of GPR signals that form the in-phase axes showed the presence of a random component, which significantly affects the recorded GPR wave field. Using the results of field measurements of horizontally layered media as an example, a change with increasing depth of the main statistical characteristics, as well as the distribution of amplitude values (normal–uniform–normal) was established. The results obtained will be very useful both in interpreting georadar measurement data and in improving the accuracy of modeling the propagation of ultra-wideband electromagnetic waves in horizontally layered media, and can also be used to refine the previously developed model of a georadar section of a frozen rock mass.

Geochemical Characteristics of Soils to the Impact of Diamond Mining in Siberia (Russia)

This article presents the results of long-term research and monitoring of the soil cover exposed to the impact of the mining and processing plant developing diamond deposits in the northeast of Siberia. The soil collection includes 436 samples of different types of Cryosols. Soil pH; soil organic carbon (SOC); granulometric composition; and mobile forms of Pb, Ni, Mn, Cd, Co, Cr, Zn, Cu, and As were identified in the samples. Multivariate statistics of the correlation matrix, clustering analysis (CA), and principal component analysis (PCA) were used to determine the sources of heavy metals. The intensity of the accumulation of chemical elements in the soil was assessed using calculated concentration coefficients (Kc) and the index of total contamination of the soil cover (Zc). In the study area, Cryosols are characterized by biogenic accumulation of Ni, Mn, and Cd in the upper soil layer and Cr, Ni, Co, Mn, and Cu in the suprapermafrost horizon. Correlation matrix, CA, and PCA revealed three distinct sources that could be considered for the investigated potentially toxic elements (PTEs): anthropogenic, lithogenic, and the source which comes from a mixed contribution of anthropogenic and lithogenic factors. The most anthropogenic contribution in the heavy metals in the study area appears in Zn, Cd, As, and Pb. The assessment interpreted that origin of Mn in the area is most likely to be a natural source. The content of Co, Cr, and Ni are controlled by both lithogenic control and anthropogenic sources. Active accumulation of mobile forms of Mn, Zn, and Ni with anomalously high concentration coefficients can be traced in the soils in the impact zone of mining operations. Anthropogenic soil contamination is spread over an area of 260 km2.

Effects of TiMoTa nano-crystalline interlayer on nucleation, adhesion and tribological behaviors of diamond coating

To investigate the influence of the transition layer on diamond nucleation and growth, the TiMoTa multi-alloy interlayers were firstly prepared on WC-6%Co cemented carbide by double glow plasma surface alloying technique, and diamond was then deposited using microwave plasma chemical vapor deposition system. The thickness of the TiMoTa interlayers increased from 1.2 μm to 2.7 μm with the deposition temperature increasing from 800 to 900 °C. Due to the formation of nano-crystalline structure and hard phase, the as-prepared TiMoTa interlayer exhibited high micro-hardness. In the diamond deposition process, the nano-carbide particles preferentially formed at the TiMoTa interlayers can effectively prevent the further diffusion of C, so the surface carbon concentration rapidly accumulates to the critical value required for the nucleation and growth of diamond microcrystals. Finally, a microscale wear-resistant diamond coating with good adhesion was grown on the transition layer, the crack propagation radius of the diamond coating is ∼162 μm, and can reach Hf 2–3 grade. Therefore, our prepared TiMoTa nano-crystalline interlayer provides a new path for the development of a high-quality diamond coating with good adhesion on cemented carbide.

Diamond formation beneath the Coromandel area, southwestern São Francisco Craton – The role of re-fertilization and subduction

The lithospheric mantle underpinning the Alto Paranaíba Igneous Province , southwestern São Francisco Craton , was investigated through a study of 82 diamonds and their mineral inclusions from the Coromandel (Douradinho River), Verde River (northern Coromandel), Abaeté, Frutal, and Romaria deposits. Mineral inclusion abundances show that lherzolite is the main diamond source-rock, followed by eclogite , harzburgite and minor websterite. The limited chemical depletion recorded in lherzolitic inclusions suggests a post-Archean origin or modification of the lithospheric mantle beneath this part of the São Francisco craton. Sinusoidal rare earth element patterns for lherzolitic garnet inclusions indicate variable but overall low degrees of metasomatism by fluids or silico‑carbonatitic (proto-kimberlitic) melts. These results contrast with previous studies on mineral inclusions in diamonds (Canastra range, southern Coromandel; Rio da Prata system, northeastern Coromandel; our new data on the Frutal area, southwestern Coromandel), where a dominance of harzburgitic inclusions documents a more depleted, likely Archean, cratonic root. Bulk rock compositions reconstructed from eclogitic and websteritic inclusions establish a clear link between subduction processes and diamond formation in the Coromandel region. Calculated bulk rare earth element patterns match typical sections of upper oceanic crust , where plagioclase accumulation is uncommon. Pyroxene inclusion-based geothermobarometry indicates that lherzolitic and websteritic diamonds formed and last resided along a ∼ 39 mW/m 2 model geotherm. Projection of eclogitic garnet-clinopyroxene pairs onto this 39 mW/m 2 geotherm places their origin near the base of the lithosphere (> 180 km depth). Low nitrogen contents and high aggregation states (up to 100 %B) indicate that eclogitic, websteritic, and part of the lherzolitic diamond populations experienced extended (2.0 Byr) mantle residence at high temperatures (> 1200 °C). The similarity in mantle residence temperatures and the shared presence of minor negative Eu anomalies for eclogitic and websteritic diamonds and their inclusions may be indicative of a common origin, following emplacement of subducted oceanic crust beneath the São Francisco Craton margin likely during a Paleoproterozoic orogeny (2.2–1.9 Ga). Based on our results, future exploration efforts in the Alto Paranaíba region should shift their focus from harzburgitic to lherzolitic and eclogitic indicator minerals to find new diamond deposits and kimberlites in this area. • Lherzolite and eclogite main diamond substrates in Alto Paranaíba Igneous Province. • Moderate olivine Mg# and rare G10 garnets indicate mild SCLM depletion. • Lherzolitic substrates affected by fluid or silico‑carbonatitic melt metasomatism. • Eclogitic and websteritic diamonds derived from base of lithosphere. • Eclogitic diamonds linked to Paleoproterozoic (2.2–1.9 Ga) subduction.

Влияние разрывных нарушений на систему опережающей дегазации проектируемого рудника «Мир»

Aspects of the gas content of the host rocks of the bedrock diamond deposit of the Mir kimberlite pipe are considered. The intervals of gas-saturated reservoirs in the interval of the Tolbachan were studied and identified, the effect of discontinuous disturbances on their fluid saturation is given. The research results allow to predict the nature of gas occurrences and the amount of reservoir gases during the mining of the Mir tube indigenous diamond deposit in the Tolbachan formation interval. The efficiency of the proposed method of degassing host rocks is confirmed by the already achieved significant (20–30 times) drop in the flow rates of observed gas manifestations at analogous deposits, and the absence of cases of gassing in the opening workings and stopes of mines over the past 3–5 years. Degassing of host rocks is carried out in two stages. At the first stage, a circular system of vertical leading wells is drilled to the full capacity of the production block. Calculations showed as follows: the system of advanced degassing of reservoirs of the Tolbachan should consist of 64 wells with a depth of 350 m each. To ensure safe mining, drilling of holes should be carried out directly from the underground mine workings, using blowout control equipment designed for a pressure of 225–250 kgf/cm2. Subsequently, the residual pressure in the massif will not exceed 30–40 kgf/cm2, which will allow to move on to the second stage of massif unloading — drilling of slightly inclined wells directly from the faces of the underground mine workings under construction.

Книга очерков и исторический роман И. И. Винокурова-Тагуса: модусы художественности

The aim of our study is to identify the aesthetic dominants and traditions of historical narrative in the book of essays and the historical novel “Love in the Yaranga” by I. I. Vinokurov-Tagus. The scientific novelty lies in the introduction of the Evenk novelist’s work into the research field and the description of the artistic mode of national historical prose. The results of the study are formulated in the following theses: the book “Deer Paths to Diamond Deposits”, written in the genre of memoirs, was a prologue to the historical novel by I. I. Vinokurov-Tagus. The genre-typological features, main motives, typical characters are revealed in the novel “Love in the Yaranga”. The combination of realistic and romantic principles of representation in prose allowed I. I. Vinokurov-Tagus to raise the theme of national self-consciousness at a new level and continue the traditions of the historical prose of the peoples of the North.

Comparison of heteroepitaxial diamond nucleation and growth on roughened and flat Ir/SrTiO3 substrates

Heteroepitaxial diamond deposition on iridium substrates allows production of single crystal diamond layers on large area that is difficult to achieve with homoepitaxy. Critically important is the first stage of the process when diamond nucleates on Ir upon biasing (a voltage applied to the substrate). Here, we compared the heteroepitaxial nucleation and successive growth of diamond thin films in a microwave plasma CVD reactor on Ir/SrTiO3 substrates with different surfaces modified by bias voltage. The roughened surface consists of furrows and ridges while the flat surface is a little wrinkled. The film morphology, crystal quality and stress are characterized with SEM, AFM, TEM, X-ray diffraction and Raman spectroscopy. It is found that the film on the roughened Ir surface has a lower roughness, smaller mosaic spread, but a larger residual stress than the film deposited on the flat Ir surface, which mainly originates from the difference in the domain density. By comparing diamond (111) lattice spacings of different positions from the Ir-diamond interface, it is inferred that diamond nucleation could occur at the furrows and then overgrow the ridges for Ir-roughened sample while diamond may nucleate at the wrinkle and flat regions for Ir-flat sample. These finding are helpful in understanding of details of diamond film heteroepitaxy, and in searching the ways to improve their crystallinity.

Thermal history of diamond from Arkhangelskaya and Karpinsky-I kimberlite pipes

This work studies and compares the main morphological, structural, and mineralogical features of 350 diamond crystals from the Karpinsky-I and 300 crystals of the Arkhangelskaya kimberlite pipes. The share of crystals of octahedral habit together with individual crystals of transitional forms with sheaf-like and splintery striation is higher in the Arkhangelskaya pipe and makes 15 %. The share of cuboids and tetrahexahedroids is higher in the Karpinsky-I pipe and stands at 14 %. The share of dodecahedroids in the Arkhangelskaya and Karpinsky-I pipes are 60 % and 50 %, respectively. The indicator role of the nitrogen-vacancy N3 center active in absorption and luminescence is shown. Crystals with the N3 absorption system have predominantly octahedral habit or dissolution forms derived from the octahedra. Their thermal history is the most complex. Absorption bands of the lowest-temperature hydrogen-containing defects (3050, 3144, 3154, 3188, 3310 cm−1, 1388, 1407, 1432, 1456, 1465, 1503, 1551, 1563 cm−1), are typical for crystals without N3 system, where in the absorption spectra nitrogen is in the form of low-temperature A and C defects. The above mentioned bands are registered in the spectra of 16 % and 42 % of crystals from the Arkhangelskaya and Karpinsky-I pipes, respectively. The diamond of the studied deposits is unique in the minimum temperature (duration) of natural annealing. Based on a set of features, three populations of crystals were distinguished, differing in growth conditions, post-growth, and thermal histories. The established regularities prove the multi-stage formation of diamond deposits in the north of the East European Platform and significant differences from the diamonds of the Western Cisurals. The results suggest the possibility of the existence of primary deposits dominated by diamonds from one of the identified populations.

Prospecting models of primary diamond deposits of the north of the East European Platform

As a result of a comprehensive study of the geological structure and diamond presense of the northern part of the East European Platform, generalization of the data accumulated by various organizations in the USSR, the Russian Federation, and other states, three main prospecting models of primary diamond deposits have been identified and characterized: Karelian, Finnish, and Arkhangelsk. Geological, structural, mineralogical, and petrographic criteria of local prediction, as well as the features of the response of kimberlite and lamproite bodies in dispersion haloes and geophysical fields, are considered using known examples, including data on the developed M.V.Lomonosov and V.P.Grib mines. It is shown that the most complicated prospecting environments occur in the covered areas of the Russian Plate, where, in some cases, the primary diamond-bearing rocks are similar in their petrophysical properties to the host formations. The buried dispersion haloes of kimberlite minerals in the continental Carboniferous and Quaternary deposits are traced at a short distance from the sources. Differences in the prospecting features of magnesian (Lomonosov mine) and ferromagnesian (Grib mine) kimberlites are also shown. Conclusions about the diamond potential of the model objects of various types are given in this paper.

Plasma etching for carbon materials by inward RF plasma apparatus

ABSTRACT Diamond has high wear resistance and shape stability, and poly-crystalline chemical vapour deposition (CVD) diamond is difficult to mechanically process because of cleavage and wear anisotropy. On the other hand, diamond can be removed under an oxidising atmosphere with O2 as the etching gas by reactive ion etching which is processing using plasma. In this study, the fabrication of an inward radio frequency (RF) plasma apparatus and the possibility of a removal process for carbon materials such as CVD diamond film and graphite plate by using it were investigated. OES, confocal laser scanning microscope and Raman spectroscopy were used for the evaluation of the etching. It was confirmed that the inward RF plasma apparatus fabricated could be applied to plasma etching for carbon materials. In addition, it was suggested that carbon materials were etched as CO with O2 in the atmosphere, and amorphous structures were etched preferentially over crystalline ones.

A Review of the Geology of Global Diamond Mines and Deposits

A Review of the Geology of Global Diamond Mines and Deposits

Approaches to the diamond potential of the Siberian craton: A new paradigm

Synthesis of new and published data on diamond occurrences in the Siberian craton provides a perspective on the diamond potential of the region in terms of a new paradigm. The new diamond potential paradigm for the Siberian craton includes several main postulates:(i) existence of Precambrian diamond sources;(ii) diversity of Precambrian primary diamond deposits and related diamond populations; prevalence of diamond varieties associated with suprasubduction magmatism;(iii) single kimberlitic type of Phanerozoic primary diamond deposits;(iv) Middle Paleozoic kimberlites as the main hosts of economic primary diamond deposits.Exploration for Precambrian primary diamond deposits is unreasonable: they are detectable within limited basement exposures and may be deeply eroded; their types and signatures remain unknown, which obscures the exploration targets. However, diamond may exist in Mesozoic and Cenozoic placers derived from such deposits.On the other hand, Middle Paleozoic kimberlites, including those in the northeastern Siberian craton, may store economic amounts of diamond; indicator minerals in placers from these kimberlites can be discriminated from their counterparts of poor or barren Mesozoic kimberlites using specially selected mineralogical criteria described in the paper. The new paradigm highlights the true diamond potential of the Siberian craton and allows outlining realistic exploration objectives for primary and placer deposits.

Caracterização textural, mineralógica e a lavra de aluviões diamantíferos nos garimpos da chapada diamantina, Bahia / Textural and mineralogical characterization and the mining of diamond-bearing alluvial deposits in the chapada diamantina, Bahia

Diamond prospectors, who have been mining for more than 150 years in the Chapada Diamantina, are now trying, through initiatives such as the Andaraí prospectors cooperative, to formalize the exploitation of the diamond alluvial deposits in this region of Bahia. The sequence of operations for mining and processing these alluvial deposits in semi-mechanized garimpos, is generally determined by the geological conditions of the deposit and the availability of water resources. This research contributed to the characterization of secondary diamond deposits and to the understanding of how the mining of these deposits occurs in the Chapada Diamantina. It evidenced the characteristic profile of these alluvial deposits that present the diamondiferous gravels accumulated at the base of the sedimentary sequences, sterile matter formed predominantly by sand and clay, a configuration very similar to that observed in the deposits found in the tributaries of the Paraguaçu River, present in the study area. The main objective of this paper was to conduct a mineralogical and textural characterization of the alluvial deposits in the municipality of Andaraí in the vicinity of the Paraguaçu River and of the operational conditions of mining by the miners. The results point to a high sterile-mineral ratio for the exploitation of these deposits and detail the processes of mining and treatment of the diamond gravel for concentration of the Diamonds.

Воздействие разработки месторождения алмазов им. М. В. Ломоносова на экосистему реки Золотицы

The development of the Lomonosov diamond deposit is underway on the territory of the Arkhangelsk region. Saponite rocks pollute the environment. The Zolotitsa River ecosystem is under significant anthropogenic pressure due to discharge of drainage water into the river. The study purpose is to assess the impact of the diamond deposit development on the discharge and chemical composition of the Zolotitsa River waters using statistical methods. The main data source for the study was the State Water Cadastre. As a result, the researchers proved no significant changes in the discharge and chemical composition of the Zolotitsa River waters. The only exception is the decrease in the dissolved oxygen content. However, the fact requires further study to identify the true causes of the trend.

Morphology and FTIR Characteristics of the Alluvial Diamond from the Yangtze Craton, China

A total of 48 natural alluvial diamonds from the Yangtze Craton, China, also called Hunan diamonds, were studied using morphology and IR spectroscopy. These diamond samples, collected downstream of the Yuan River, Hunan Province, with unknown host-rock source(s), were observed by scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR). Most Hunan diamonds are monocrystal forms of octahedra, tetrahexahedra (THH) and dodecahedra; octahedral–rhom-dodecahedral transitional behaviors and irregular forms are also visible. Trigons and tetragons, terraces and shield-shaped laminae are surface features that frequently indicate dissolution and reabsorption; green and brown spots, network patterns, and other mechanical abrasion marks are typical evidence of long-time deposition and transportation of Hunan diamonds. The main types of Hunan diamonds are type IaAB and type Ⅱa. Diamond samples have a wide range of total nitrogen content (Ntot) from 196–1094 ppm. Two populations are distinguished by two-peak distribution models of NA (A-center concentrations) and %B (proportion of aggregated nitrogen). Hunan diamonds are low in structure hydrogen (0.03–4.67 cm−1, mostly below 1 cm−1) and platelets (0.23–17 cm−1, mostly below 2 cm−1). Moreover, there is a significant positive correlation between the hydrogen correlation peak and Ntot, which is similar to Argyle diamonds. The temperature conditions of the diamond formation have been estimated at 1075–1180 °C, mainly conforming to the kimberlite diamond range. Besides, some samples with slightly higher temperatures are close to the ultramafic-related Juina diamonds. Therefore, the FTIR characteristics analysis and comparison indicate the multiple sources of Hunan diamonds.