Assessing the Mercury Usage in Small Scale Jewellery

This study was conducted for identification of potential mercury free alternative methods for this process.

 Accordingly, gold separation through Aqua regia, hypochlorite and Nawasaram were identified as the potential

 alternative methods and they were evaluated for the better substitute for mercury process. Results of the study 

revealed that aqua regia is the cost effective and efficient method. However, this method produces a huge amount 

of hazardous gases. In contrast, hypochlorite is an environmentally friendly method which also shows a very good

 Efficiency with a reasonable cost. Thus, hypochlorite is considered as the most potential Alternative.

Introducing Non-mercury alternative for Gold separation in 

small scale Jewellery Sector 

This pilot study was conducted focusing the Western province of Sri Lanka, to assess the 

Hg exposure level of individuals engaged in small scale jewellery sector through a Bio-chemical 

Investigation. The study results signify the variation in urine mercury levels between the various 

Exposure subgroups. Among the study population, waste gold separators were identified as the 

Subgroup that showed high levels of mercury in their urine samples.

Introduce the most effective and efficient color and clarity enhancement

for Semi-Precious gem minerals found in gem gravel beds in Sri Lanka.

Authors:

M.N.M. Rifkhan, G.G.C.N. Wewegedara, R.M.N.P.K. Jayasinghe, T.S. Dharmaratne

Note:

This technical report was published under the research project of  Introduce the most

effective and efficient color and clarity enhancement for SemiPrecious gem minerals

found in gem gravel beds in Sri Lanka with the funding of National Science Foundation (NSF).

 Dharmaratne T.S., Premasiri H. M. R., Jayasinghe 

 R.M.N.P.K., Illangasinghe I.K.M.S.C.K 

 and Wickremaarachchi W.A.K.C., 2011. 

 Gem Potentiality of Wellawaya Divisional Secretariat. 

 Gem and Jewellery Research and Training Institute, Sri Lanka.

 Dharmaratne T.S., Jayasinghe R.M.N.P.K. and Herath K.R.P.K., 2006. 

 Exploration and Identification of New Gem Deposits at Naula Divisional 

 Secretariat in Matale District, Sri Lanka. Gem and 

 Jewellery Research and Training Institute, Sri Lanka.

 Dharmaratne T.S., Jayasinghe R.M.N.P.K. 

 and Herath K.R.P.K., 2006. Feasibility Study 

 on Magnetite Deposit in Horakagodakanda Range 

 in Buttala, Sri Lanka. Gem and Jewellery Research 

 and Training Institute, Sri Lanka.

Dharmaratne T.S., Jayasinghe R.M.N.P.K. 

and Herath K.R.P.K., 2006. Feasibility Study on 

Gem Mining in Naimulla Land in Hanwella, Sri Lanka. 

Gem and Jewellery Research and Training Institute, Sri Lanka.

Dharmaratne T.S., Jayasinghe R.M.N.P.K., 

Jayamali M.K.C. and Wijewardhane S. 2014. 

Eco-Friendly Gem Mining Techniques For Sustainable 

Development in Ratnapura District, Sri Lanka. 

Gem and Jewellery Research and Training Institute, Sri Lanka.

Establishing A Baseline for valuation of gemstones 

The computer-based ValGem system estimates the minimum value of colored gemstones 

based on user selection and predefined references. It is a remote access system allowing 

input data from a remote end. The model demonstrated over 90% accuracy, suggesting a 

well-fitted criterion for gemstone valuation. This system is suitable for estimating the minimum 

market value of specific colored gemstones.

Pilot study on exposure assessment of Mercury in small 

scale jewellery manufactures in sri lanka. 

This study was focused on gathering information on mercury usage, process involved, associated 

health effects and alternative methods in Small Scale Jewellery Sector (SSJS) through a structured 

questionnaire survey. Results of the study revealed that SSJS is a major sector that uses mercury

in a considerable amount in Sri Lanka. Most of the individuals are not aware on harmful effects of 

mercury. Very few were aware on the toxicity of mercury but they do not use any safety precautions 

when handling mercury. They usually touch mercury with bare hands and heat mercury in open flame 

where Hg vapour can easily mixed with atmospheric air and get inhaled. Lots of health issues were 

observed with the people who engaged in this industry.

Promoting Diverse Value Addition techniques for Gemstones 

This technical report delves into advancements in gemstone processing across four key research 

areas. It addresses challenges in geuda industry methods by employing a novel tube electrical 

furnace for enhanced color and clarity in Silky Geuda. The report introduces a groundbreaking 

technique for intensifying the yellow color in Kownagu Yellow Sapphire, and explores innovative 

approaches to enhance the blue color of Tanzanite using a tube electrical furnace. Additionally, 

it tackles the clarity improvement of Red Geuda, presenting a new technique utilizing the LAKMINI 

gas furnace.

Study on Economically Valuable Minerals available in the

Gem Bearing layer

The gem-bearing sediments are a source for economically important heavy minerals 

and metals, and rare minerals. But the usual practice in Sri Lanka is discarding the 

sediments in gem gravel layer after recovering gems. The study assessed the possibility

 of extraction economic minerals in this layer expecting miners might earn an extra income 

from it. The heavy mineral suite in the study areas consists predominantly of ilmenite, garnet,

 magnetite and monazite. Other identified heavy minerals are hornblende, spinel, tourmaline and zircon.

Value Addition of Gemstones by New Technical Treatments

jewellery manufactures in sri lanka.

 This technical report delves into advancements in gemstone processing across four 

key research areas. It addresses challenges in geuda industry methods by 

employing a novel tube electrical furnace for enhanced color and clarity in Silky Geuda. 

The report introduces a groundbreaking technique for intensifying the yellow color in Kownagu 

Yellow Sapphire, and explores innovative approaches to enhance the blue color of Tanzanite 

using a tube electrical furnace. Additionally, it tackles the clarity improvement of 

Red Geuda, presenting a new technique utilizing the LAKMINI gas furnace.

Radiactivity Survey On Godakawela Gem Field In Sri Lanka- to Identify

The Deposition Type Of The Unknown Radioactive Mineral.

This study investigates the gem-rich Godakawela region in Sri Lanka, known for its unique 

radioactivity. Unlike global practices, Sri Lankan gem exploration relies on sedimentological and 

geochemical analysis rather than in-situ radioactive surveys. The research employs a plastic 

scintillation detector and NaI scintillation detector to measure gamma dose rates, revealing a 

significant radioactive anomaly. The presence of zircon and tourmaline suggests a primary origin,

 supported by X-ray diffractogram peaks corresponding to euxenite, pending confirmation through 

recrystallization analysis with heat treatment.

Introduce The Most Effective And Efficient Colour And Clarity Enhancement

For Semi-Precious Gem Minerals Found In Gem Gravel Beds In Sri Lanka

This technical report describes the project progress for the mentioned period. Enhancement 

methods experimented for semi-precious gem materials for instance heat treatment, surface coating, 

diffusion, bleaching and dying are discussed. Further, the ground-breaking results of the heat-treatment 

experiments of kiri kottara and reddish brown zircon are elaborated in detail. 

Investigating On Effect Of Localization To Colouration Of Low

Quality Corundum(Geuda) By Heat Treatment

 This study investigates the variability in color enhancement of milky geuda stones in Sri Lanka's 

gem-bearing regions. Focusing on 53 geuda samples from Ratnapura, Ridiyagama, Okkampitiya, 

Bakamuna, and Katharagama, the research employs microscopy, ED-XRF, FTIR, Raman, and UV-VIS 

spectroscopy. Results reveal that the degree of color enhancement differs with Ti, Fe, and V impacting 

the process. FTIR proves effective in identifying heat-treated blue sapphires, emphasizing the significance 

of localization in color enhancement. 

Investigation Of Impact On Water Quality By Gem Mining In Kalu Ganga,

Sri Lanka

This research investigates the adverse effects of riverbed gem mining on Kalu Ganga. The study reveals 

significant sedimentation and heavy metal pollution in the surface water system due to illegal gem mines 

in Rathnapura District. Continuous mining imparts a brownish hue to the river, and heavy metal concentrations 

during mining exceed safety limits, with Fe < Mn < Cr< Cu< Pb< Cd The river s pH ranges from 6 to 7, and 

maximum turbidity, at 49.2 NTU during gem mining, indicates compromised water quality beyond acceptable limits. 

Bibile Divisional Secretariat Division.

Corundum (blue sapphire, yellow sapphire, star sapphire and geuda), spinel (blue, purple, pink), tourmaline 

(yellowish brown, rarely dull green), garnet (most commonly pyralspite series’ garnets) are the commonly 

found gem varieties in the division while any zircon encounters were rarely reported. The gem potential map denotes

Haputale Divisional Secretariat Division

The gem gravel bed sits 20 feet below ground level and approximately 2 feet thick. Golden and yellow 

sapphires, blue sapphires were found there but were small in size. Kithulgahawaka region near Aluthwela 

yields yellow sapphires,tourmaline, spinels, and cats’ eyes as small stones. The gem potential map denotes

Kahattewela-Ranjallawa-Kahagollagem field, Haputhale oya gem field, Horadorowwa gem field, and 

Diyathalawa-Ellagama gem field

Eheliyagoda Divisional Secretariat Division

Getahetta corundum pockets are a unique gem occurrence that occurs between two shear zones. 

Key gem types found are all varieties of sapphire, spinel, zircon, tourmaline and garnet varieties.

 It is concluded Eheliyagoda area has a high gem potentiality.

Kiriella Divisional Secretariat Division

The gem occurrences in Kiriella area are mainly of metamorphic/metasomatic origin. All alluvial, 

eluvial and residual deposits are observed as sedimentary types. Out of these alluvial deposits are 

found associated with the lower order streams of Kalu ganga and Kuru ganga. Epitawala, Ellagawa, 

Yatipawwa, Galathura, Dodampe, Mudunkotuwa, Matuwagala, Nedun viharaya premises have been

 identified as high gem potentiality areas. 

Niyagama Divisional Secretariat Division

The generation of chrysoberyl, alexandrite, garnet, zircon, yellow, and green tourmaline gems is 

confirmed through the disintegration and decomposition of quartzo feldspathic gneisses, Calc 

Gneiss and khondalite basement rocks 

Bandarawela Divisional Secretariat Division

Four types of gem fields were discovered based on field observations: Mahaulpotha-Dulgolla gem field, 

Bambaragama gem field, Ettalapitiya gem field, and Icelabewatta gem field.

Thawalama Divisional Secretariat Division

Based on the field and laboratory observations, there are several locations consisting of primary 

and secondary gem deposits. Most of the secondary deposits are situated very close flat areas 

to the Gin Ganga, Thalangalu Ela, Bihiriya Dola Ela and Hulanda Oya.

Medagama Divisional Secretariat Division

The gemstones found in this area consists mainly Yellow Sapphire, Blue Sapphire, Geuda, Spinel, 

Tourmaline, Garnet, Zircon and Moonstone.

Haldummulla Divisional Secretariat Division

Geologically and geo-morphologically, Haldummulla DSD area has high favorable conditions 

for the formation and deposition of the gemstones.

Wellawaya Divisional Secretariat Division

Gem fields in Wellawaya DS are much more complex. There is a higher possibility of having 

both primary and secondary gem deposit occurrences. The gem fields in the area are subcategorized 

based on their occurrences for clear description.

Buttala Divisional Secretariat Division

The gem potential map denotes Yudaganawa garnet gem field, Pellasara Ekanite gem field and 

Okkampitiya Maligawila gem field as the primary gem occurrences while Manik Ganga gem field, 

Kuda Oya gem field and Kumbukkan Oya gem field as alluvial deposits. 

Moneragala Divisional Secretariat Division

Depth to the gem bearing gravel layer differ between 1-6 meters depending on the location. Sapphire 

(blue sapphire, yellow sapphire, pink sapphire, geuda), zircon, tourmaline, garnet and spinel are the 

commonly found gem varieties of the area. 

Pelmadulla Divisional Secretariat Division

The gem occurrences of the division could be named mainly as the Wey Ganga alluvial deposit, 

Nilagama eluvial deposit and Denawak Oya alluvial deposit.