T » CM tMA CHAT. kiM A. st 340 1-2/2014. Ir. 29-36
MQT SO DAC DIEM NGOC HQC CUA SPIIVEL VUNG LUC YEN, YEN BAI
PHAM VAN LONG', VINCENT PARDIEU', GASTON GIULIANI, NGUY TUYET NHUNG' PHAM THI THANH HIEN^ PHAM DlTC ANH', NGUYEN NGOC KHOI*, HOANG QUANG VINH'
' Trung Idm Nghien ctiu Kiim dinh Ddquyvd Vdng. 91 Dinh Tien Hodng. Hd .Vdi Supervisor Field-Gemmology. GIA Laboratory Bangkok.
' Universite Paul Sabatier. GET, Toulouse and Vniversile de Lorraine CRPG UMR 7358 C.VRS-UL BP 20, 54501- Vandauvre-les-Nancy cedex. France '
^ Trung Idm Nggc hpc. Hdi Dd quy V 'iel Nam
^ KhoaDiachdt. Trudng Dgi hpc Md - Dia chdt. DdngNgac. TiiLiem, HdNdi Khoa Dja chdt, Trudng Dgi hpc Khoa hpc Tu nhien. Nguyin Trai. Thanh Xudn. Hd Ngi Vifn Dia chdt. Vien Hdn lam Khoa hgc vd Cdng nghi Viet Nam. Phd Chiia Lang. Ddng Da Hd Ngi
Tdm tdt: Khodng vgt spinel vimg Luc Yin (linh Yin Bdi) dupe phdt hiin tit ndm 1985 cimg vdi cdc thdnh tgo ruby vd saphir trong sa khodng Spinel vimg Lyc Yin cd rdt nhieu mdu sdc khdc nhau; do. hdng tim. xanh nude biin. xanh da trdi.... Logi spinel cd chdt lupng ngpc cao dimg di Idm hdng trang sue chu yiu dupe khai thdc trong sa khodng trong khi do logi spinel trong dd gdc (dd hoa) thudng cd chdt lupng ngpc th^ vd chd yiu dimg lam mdu suu tgp. Mdu sdc ciia spinel Lyc Yen thay ddi luy thupe vdo hdm lupng ctia cdc nguyen td tgp chat gdy mdu. Sv cd mat cua crdm (Crfii) tgo ra cdc Img mdu do vd hdng Su kit hpp giOa Crfi, vd FeO tgo mdu lim. Cobalt (CoO) tgo mdu xanh lam. Sdt (FeiPs) tgo rg tdng mdu ndu vd dnh phdt ndu... Td hpp bao thi dd phdt hiin bao gdm apatil. rutin, goelhil, orthoclas. vd cdc bao the dgng linh thi dm.
I. GI(^THI$U
Vimg md Luc Yen tiiupc tinh Yen Bdi, ndm cdch Hd Npi 270 km vi phia tdy bic.
Tir Hd Npi cd thi di bdng tau hda hodc d td tfieo Quoc Ip sd 2 len Yen Bai. Sau dd tir tfidnh phi Yfn Bdi di tiip 70 km tiieo qudc Ip 70 s6 din tfu Mkn Yen Thi la tnmg tam huyfn Lyc Yen.
Ndm 1985 ruby vd saphir dupe phdt hien tgi Lyc Yen, tmh Yen Bdi ttong qud trinh Idp ban dd dja chat khu \vc. Ndm 1987 Cdng ty Dd quy Vift Nam (VINAGEMCO) dupe tfianh Igp va bit diu vifc khai tfidc mby \a saphir tgi mpt sd difm md viing Lyc Yea Vifc khai tfidc cd quy md diu tien dupe tiin hanh tgi Khoan Thdng, tiring qud tiinh khai thdc luby \-d saphir thi phdt hifn dupe mpt lupng k5in spinel di kem trong sa khoang, chung bao gdm cac tinh thi dupe mdi ttdn
mpt phin hodc dgng manh va \m nhiiu mdu sic khdc nhau: dd, hdng, dd phdt ndu. phdt tim vi cd dp trong suit cao thich hpp cho vifc san xuit hang ttang siic. Sau dd, mpt loat cac diem md vimg An Phii cho nhiiu spinel cd mdu sdc khdc nhau; mdu lam dupe khai tiiac nhiiu o Cd Ngan, cac mdu dd, hing, tim ^ nhiiu d cac khu vyc Hin Om, Khau Nghiin, Vang Sao, Nuijc Ngap, Ngdi Lgnh, Cdng Trdi. Nhiing ndm gin ddy spinel mdu xanh da trdi dupe khai tiiac nhieu d Liing Thin, Bdi Son.
Cho din nay (diua cd mdt cdng ttinh nghien ciiu nao rieng cho ^nnel vimg Lyc Yen, chiing chi la nhiing cdng tiinh nghien ciiu le te, hodc dupe di cap khdng chinh tfiiic ttong (»c di dn tim kiim ruby vd saiAir. Mdt si bai viit chuyen di vi ddc tinh cua spind ttong cac Hdi ttiao quoc ti^ hodc
29
cac bai gidi tiiifu ngdn vi spinel cua mdt sd lac gid Koivula J.I., Kammerling R. C . Fritsch E. (1993), Smitii C.P., Darenius E.Q., Mayerson W.M. (2008). Senoble J . B ' (2010), BlauwetD. (2011).
Bai vift nay ttinh bay mdt si dac diim ngpc hpc cua spinel viing Lyc Yen.
II. BAC DI£M D!A CHAT CUA CAC
THANH TAO CHI/A SPINEL
Khu vyc Lyc Yfn thudc ddi Ld Gam nam vf phia ddng cua dih gay Sdng Chay.
Cdc tiianh tgo dja chit ttong khu vuc bao gdm hai phan vi dja ting la hf ting Thac Ba va hf ting An Phii. Hf ting Thac Ba bao gdm chu yiu Id cac da phiin tiigch anh hai mica xen kep cac da phiin tiiach anh biotit bi migmatit hda va gnds hda vdi cdc muc dp khac nhau, ddi cho xen kep cdc tiiau kinh vdi hodc quartzit. He ting An Phii chii yeu Id da hoa calcit cd xen da hoa dolomit chiia cdc khoang vat di kem cd phlogopit, fiischit, graphit (Giuliani G et
al. 2003a [3]).
Trong sa khoang tiiudng Id cdc tinh tfif bj mai ttdn. cac manh v5 sdc canh d cdc mdu khac nhau: dd. hdng, ndu do, tim. xanh lam va xanh da tttri.... Cac san phim khai tfidc dupe ttong sa khoang tfiudng cd df tionB sudt cao va fluch hpp cho vifc Idm htoe trang siic.
Tgi khu vyc An Phii gdp spind cd nhiiu mau khac nhau. Spind mdu xanh lam gdn nhieu d Khau Ca, Cd Nggn. Spind mdu d6 hong va mau tim dupe khai tiiac nhiiu ttong sa khoang cac khu vyc May Thupng Cing Trdi va Minh Tiin (Blauwet D.,'2010.
2011[I,2]). Spmd mau xanh da ttdi dup^
khai tfidc nhieu d khu vuc Liing Thin vd B3i Son (Hinh 1).
Spind vung Lyc Yfn dupe khai tfik tiong hai kifu ngudn gdc Id ttong dd gic vd ti-ong sa khoang (dpc tiieo cdc khe suii va cac bai bdi aluvi).
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^'^'•'<''^^i''^^'^ngLycYinvdcdovitrikHaithdcspinel
"m cac mau sdc khdc nhau.
Spinel trong da gdc dupe khai thdc d nhifu noi trwig khu vuc, vdi cac vi tii chian uu thf d cdc vung Cdng Trdi, May Ha va Mdy Thupng. Ve mdu sdc, sfinel ttcmg da gdc khu vyc nay chii yeu cd mdu dd, dd nhgt, tun, ndu va den. Ve chit hipng. cac tinh the spinel trong da gdc thuong due va chi thich hpp cho vifc lam miu sim tap, hodc dupe ngudi dan dja phuong liy ra dung df lam ti'anh dd qay.
Spinel mau xanh lam gidng saphir gap nhieu d khu vuc Khau Ca va Cd Nggn (xd An Phii). trong khi dd spinel mau xanh da ttdi dupe khai thac nhieu d c ^ khe sudi khu Liing Thin va Bai Son (Senoble J.B., 2010 [9]).
HL CAC OAC OI^M NGQC HQC CUA SPINEL
1. Thanh phdn hoa hpc
Tdi^ cdng 41 miu (Bang 1) cac mdu
Anh 1. Diem khai ihdc spinel trong dd gdc a Cdng Trai (ben trdi) vd td hpp khodng vdi spinel, pargasil, humit trong dd hoa (ben phdi).
Td hpp cpng sinh khoang v^t di cimg vdi spinel tnmg dd gic tiiudng gdp Id pargasit, dolomit, olivin, humit, phlogopit vd giaphit (Hofineister IV.. 2001 [4];
LongP.Vetgl. 2004[7,8]).
Spinel dxKjc khai thdc trong- sa khodng ciing cd rat nhieu cdc mdu khdc nhau. Tgi khu vyc Khoan Thing vd Bdi Chudi chu yeu gdp cdc mdu dd, dd nhgt den hdng (Koivulg JI. 1991, 1993 [5. 6J).
Trong sa khodng dpc theo cac khe suii khu vyc An Phii thuong gdp spinel mdu dd. dd ndu, u'm va hong
Anh 2. Spinel co mdu khdc nhau vimg Luc Yen (dd che tdc)
31
Wi
khac nhau dupe phan tich vd cho tiiiy cac nguyen ti t ^ chat chu yiu Id V, Ni, Zn, Ti, Cr, Fe, Co, mdt s i nguyen td khac gap it hem nhu Mn va Ca.
Kit qua phan ti'ch cho tiiiy, loai spinel mdu dd cd ham lupng Cr203 cao n h ^ chiing dao ddng tiong khodng 0,968-1,088%. Ham lupng Cr203 giam di d cac tdng mau dd nhgt hon cho din mau hdng (030-0,360%), ttong khi dd d logi spinel mau nau tdi hdng nhat tfii ham lupng CT2Q3 dao ddng tiong khodng 0,122-0,153%. Spind d cac mdu khac nhu tim, da cam vd mau xanh lam thudng cd ham lupng CrzOj tf%, chi dao dpng tiong khoang 0,012-0,056%.
Hdm lupng FeO tiiudng cao nhit ttong logi spinel cd tdng mdu ndu (dd phdt ndu hodc da cam phdt ndu) vd d logi spind cd tdng mdu tim. Spind mdu dd phdt ndu, ham lupng FeO nhiiu khi din 1,724-1,842%, tiong khi d logi cd tdng mdu da cam phdt ndu hdm lupng FeO tiiudng dao dpng ttong khodng 1,053-1,127% vd d logi spind cd tong mdu tim t5hi ham lupng FeO dao dfng trong khodng 1,078-1,136%. Diiu ndy cho thay sy cd mdt cua FeO Id cdn nguyen tao mau tim ciia spinel vd ddng tfidi tao nen cdc sdc phdt ndu ciia spind mau dd, mdu hdng vd mdu da cam.
^d logi spind mau lam, tfiudng quan sdt thay sy tdng cao ciia hdm lupng CoO so vdi cdc tdng mdu khac. Ham lupng CoO trong logi spinel mdu lam dgm nhiiu khi len den 0,08%. d logi mdu lam cd tdng mdu ttung binh vd nhgt tfii ham lupng CoO thudng giao dpng ttong khoang tir 0 023- 0,063%, tiong khi d cdc mdu khdc tiii'hdm lupng CoO tiiudng la tiiip (chi ttong khoang lO-Vo, chdng hgn mdu hdng Id 0.006^).015%, mdu ndu phdt hing Id 0.002-0,0.8...), diiu ndy chung .d ^ i n|dt cua CoO Id nguyfn nhan tao mdu lam cho spmel vimg Lyc Yen.
2. Cac ddc di^m ngpc hpc a) Dgc mim hinh dgng tinh the Tinh tiie spind vimg Lyc Yen cd ttong sa khoang vd ttong da gdc Id khd tirong ding, chung tfiudng cd dang tinh tfii tam mdt vdi kich tfiudc khac nhau, tfiudng Id 1-2 mm cho den 8-10 cm.
Trong da gic, spind tiiudng cd dgng tinh the hoan chinh, ddi khi ta gdp dang song tinh hogc dang tap hpp tinh tiii phdt ttiin ching len nhau, tgo nen mpt tinh tfii Idn hon la tap hpp rat nhieu cdc tinh tfii nhd.
Trong sa khoang, cdc tinh tiii spind tiiuang cd kich tiiudc tii 2-5 mm, den 1-2 cm. Thinh tfioang ta cd (hk gap tinh tfif spind cd ttpng lupng len din 3-5 kg. tfidm chi hang chyc kilogam, kich tiiudc tinh tfif nhieu khi dfn 15-20 cm Ben cgnh cdc tinh tiii dgng ty Wnh tfii phin nhieu ttong sa khodng ta gdp spind dang manh vd cd ttpng lupng 1-2 cts cho din hang ttdm carat.
D|c diim s()ng tinh: Hifn hrpng song tmh gap rat phd bifn ddi vdi spind vimg Luc Yen. cd cac tinh tiii ttong da gic vd cdc tmh tiie ngodi sa khodng. Cdc dgng song tiiJi cd tiie gdp la son^ tinh don ciia hai tinh tlie hodc tap hpp nhifu tinh tiii phdt ttiin chong Ign nhau nhung tiieo t\f hinh dgng tam mdt tgo tiidnh mpt tinh tiii don nhit cd kich tfiudc Idn.
Mdu sdc: Mdu sdc ciia spind Lyc Yen la rat phong phii vd da dgng. d day ta cd tiii gdp nhieu mdu khdc nhau vd d mii mdu ta l?i gdp d cdc tdng cd dp dam nhgt khac nhau. Trong dd, spind ttong sa khodng tiiuang CO ,ong mau dam hon so vdi spinel ttong dd gdc.
cd S m d u ' i r n ^ ^ "^"^ ™ ' ^ ^P-^' CO cac mdu do, hong, ndu, tim va mdu den Trong Wudd tgi khu vyc Bdi 301, gin khu xanh nhgt ttong cdc dd hoa cd mdu tidng
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-0,081 0,048 030 0-0 017 0-0 020 0-0 003 0-0 013 0-0 0-0,014 NiO -0,137 121 o
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70,222 69,986 -70,092 808 69, •69,792 69,470 69,721 69,233 •69,493 148
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Tiiy thudc vao mau sac cua da hoa ma cd tfie quan sat dupe spinel cd cac mau khac nhaa O nhimg khu vuc phdt triin da hoa mdu trdng ta thudng gap spinel cd mau dd hodc hdng vd hiem khi di ciing vdi cdc khodng vat khdc. 6 nhiing khu vyc phdt trien dd hoa cd mau trdng xam din tdi tfiudng gap spinel cd nhiiu mau khac nhau vd td hpp khoang vat di kem vdi spind ciing tfiudng rdt phong jrfiu. bao gdm phlogopit, pargasit, dinohumut vd fosterit
b) Tinh chat quang hpc vd ty trgng:
Cac gia tti chiit suit va ty ttpng cua spind Lyc YSn khdng khdc xa nhiiu so vdi cac gia tri ciia khoang vat spind "ly tfiuy^".
Chiet suat ciia spinel Lyc Y&i ciing tfiudng dao dpng ttong khodng 1.715-1.719.
Ty tiipng giao dpng tiong khoang 3.55-3.69, ttong do logi spinel cd mdu do, tim va mau lam ty titing tfiudng tfiip hon so vdi spind cd mau ndu, dd phdt nau, ndu do vd mau den.
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Hinh 2. Gian dd pho raman (ben trdi) vd dnh (hen phdi) cua bao thi anaiil trong spinel Luc Yen (phong dgi 30x).
« '•
I.
Pyn
Hinh 3. Gidn dd phd ramgn (bin trdi) vd dnh cua bao
Lvc Yen (phdng dgi 20x) the pyrit (ben phdi) Irong spinel
— ' • * « « - i ' ^
i
Hinh 4. Gidn do phd Raman (ben trdi) vd dnh ciia bao thi rutil (ben phdi) trong spinel Luc Yen (phong dgi 40x).Logi spinel mdu dd vd hdng tfiudng piidt quang mgnh dudi tia eye tim sdng ngdn vd sdng dai, cac mdu khdc thudng tra dudi tia eye tim.
Tinh chit ddi mdu ddi khi gdp d ^ i n d mdu xanh lam vitng Cd Nggn, spinel cdc mau khac vd d cdc viing khdc khdng quan sat duipc hi?u iing ndy.
c) Dgc diim bao the:
Ket qua nghien ctiu dd lAdt hi?n dupe ttong ^nnel viing Lyc Yai cd cac bao thi saiu ^Mtit, pyrit, rutil, orthoclas vd cdc bao thi hai pha, da i ^ dgng tinh tfii dm.
w. K C T L U A N
Spinel phdn bo rpng rai tai vimg md Lyc Yen, Yen Bai. Ve chit lupng, chi logi spinel daqc khai thac trong sa khodng la cd dp ttong suot cao hon vd cd gid tii 1dm hdng trang siic, Logi spinel tixing da gdc thudng c6 chit lupng ngpc kem hom vd thich hpp Idm mau suu tjp. Spinel vung Lyc Yen til
da dang ve mdu sdc, trong dd cd thi gdp d tat cd cdc tdng mdu khdc nhau: dd. ndu do, hdng, tim, xanh lam. xanh da trdi. den,...
Mdu sdc cua spmel Lyc Yen dirpc quyit djnh bdi ham lupng cdc nguyen td t ^ chit gay mdu. Logi mdu dd cd ham lupng CxiOi chiem uu the. logi mdu ndu dd vd mdu tim khi cd mdt dong tfidi ca Cr203 vd FeO. Khi ham lupng Cr203 giam xudng tfii spmd cd mdu hdng. Nguyen td cobalt (CoO) quyit dinh v i ^ tgo thanh spinel mdu xanh lam vd xanh da trdi.
Td hpp bao the thudng gdp ttong spinel vimg Lyc Yen gdm cd apatit.
goethit, nrtil. orthoclas. ciing vdi cdc bao the hai pha hodc da pha dgng tinh thi am phan bd tren ciing mpt mat phing ben ttong tinh thi.
LM cdm cm: Bdi bdo dupe hoan thdnh vdi sy ho tip kinh phi ciia di tdi nghien ciJru ca ban (NAFOSTED), md so 105.02- 2010.11.
35
VAN LIEU
1. Blauwet D., 2010. La mine de spindle de Lang Chap, au Nord du Viettiam. Revue de Gemmologie A.F.G.
No. 173. pp. 11-15.
2. Blauwet D., 2011. Gem News International: Spinel finrn northern Vietnam, including a new mine at Lang Chap. G&G, Vol. 47, No I, pp. 60-61.
3. Giuliani G., Dubessy J., Banks D., Hoang Quang V., Lhomme T., Pironon J., Gamier V., Phan Trong T., Pham Van L., Ohnenstetter D., and Schwarz D., 2003a. COj-HaS-COS-Sj- AIO(OH)-bearing fluid inclusions in ruby from marble-hosted deposits in Luc Yen area. Nortfi Viettiam. Chem. Geol 194 pp 167-185.
4. Hofmeister W., 2001. Moddling some mineralizations of typical Viettiamese gem deposits. Proceeding of tfie International Workshop on 'Material characterization by solid state specttoscopy: Gems gnd Minerals of Vietnam'. Hanoi April 4-10, 2001.
5. Koivula J.L, Kammerling R.C, 1991. Gem news: More on Viettiam get^
finds. G&G, VoL 27, No. 1, pp. 51-52.
6. Koivula J.L, Kammerling R.C., Fritsch E., 1993. Spinel from Viettiam' G&G, Vol. 29, No. 3. pp. 213-214.
7. Long P.V., Giuliani G., Gamier v., Ohnenstetter D., 2004. Gemslones in Vietiiam A review. Australian Gemmologist, Vol. 22, No 4, pp. 162-168.
8. Long P.v., Vinh H.Q., Gamier v., Giuliani G., Ohnenstetter D., Lhomme T., Schwarz D., Fallick A.,' Dubessy J., Trinh P.T., 2004. Gem corundum deposits in Vietiiam. The Journal of Gemmology, Vol 29, No 3 pp. 129-147.
9. Senoble J.B., 2010. Beauty and rarity A quest for Vietiiamese blue spinels. InColor, No. 14. pp. 18-23.
10. Smith C.P., Darenius E.Q., Mayerson W.M., 2008. A closer look at Vietnamese spind. InColor Spring, pp
SUMMARY
Gemmological characteristics of spinel from Lyc Yen, YSn Bdi
Pham mn ''f"J:?"%i;'"''"'P-'-d'eu. Gaslon Giuliani Ngvy Tuyit Nhung Phgm Th, ThanhHien. PhgmDucAnh, Nguyin Ngpc Khdi, HodngQuang Vinh Gem spinels were first discovered in Luc Yen rY?n na v s • , « „ ,
Witt, ruby and sapphire in nlacers Sn.wic 7 r . , P^°vince) m 1985, together colors: red. pink S e sea b ^ e L ^ I M °11 ^ ^ ' ^ ^ " ^^ ^ ^««n i" different and exploited b p f a ^ i 'reanwhiirsoi I t ^ " " ^^^''^^ ^P'"^'^ have been found low q L i t y and a r e r e d l r y ' ^ s X L ' : ^ : l Z l T ' ' r ^ f ^ ''' "^"^"^ '' changes depending on tfie concZS. Ir^ ^ ^ ^°^°'°^ ^'^'^ ^^"^ ^P'''^^
chromium (Cr^Oj) gives red S ^ n l n l ' r °f ""P"".'y elements. The presence of purple color. CobilTJ^oS) gTvesCue co,^^^^^^^ cotnb.nation of Cr.Os and FeO gives brownish luster... An ncIuLioTiseihl ' K L°" ^ l^'^'^ ' ^ " ' « ^'°^ shade and goetfiite. rutile. ortfiocla^Td n ^ e 2 , 1 " " " " ° ^ " ^ ' ' '=°"^'^""8 of apatite.
Nguai bien tdp: GS.TSKH Phan Trudng Thi.