Laboratories in Japan
AGT Gem Laboratory:
Okachimachi CY Bldg., 2nd Floor
5-14-14 Ueno, Taito-Ku, Tokyo
Tel: 03-3834-8586
Fax: 03-3834-8589
Osaka Branch Nagohori Community Bldg.,
2-5-8 Minami Senba, Chuo-Ku
Osaka, Japan
Private Corporation Yoshiko Doi, President.
All types of gemology.
Special Equipment:
FTIR Luminoscope, UV Visible Recording
Services Offered:
Issuance of Diamond Grading Report (including sorting
memo) and Gem Identification Report.
On Grading Report: Cutting style, measurments, weight,
color, fluorescence, clarity, plotting, proportion data,
finish, cut guideline.
Educactional Programs:
Based on an agreement with GIA, AGT provides GIA
educational programs in Japanese.
Hokkaido Gem Laboratory:
Kihon Bldg. 3rd Floor
No. 4, Higashi 2-chome Minami 6-jo
Chuo-ku, Sapporo
Tel: 011-512-0290
Fax: 011-512-6617
Private Corporation Ken Ozaki, President.
Gem identification diamond gradin, gem analysis, education.
Special Equipment:
UV Visible Recording Spectrophotometer, Fourier Transform,
Infrared Spectrophotometer Diamension, Colorimeter and
other gemological equipment.
Services Offered:
Gem Identification, Diamond Grading, Analysis, Education.
Color, clarity scale, cut grade for diamonds. Origins,
enhancement identification for color stones. Comments.
Educactional Programs:
Basic Course, Diamond Course, Pearl Course, Colored Stone
Course; certification is provided to those who complete
each course.

GTC Gem Testing Center of Japan:
Nisshin Bldg. 5th Floor
4-29-13 Taito, Taito-ku,
Tel: 03-3836-1388
Fax: 03-3836-1389
Limited Corporation Yoshio Suzuki, President
4Cs Diamond Grading.
Special Equipment:
UV Visible Recording Spectrophotometer, Fourier
Transform Infrared Spectrophotometer.
Services Offered:
Diamond Grading, Gem Identification.
Color, clarity, carat weight, cut grade.

Japan Technical Gem Laboratory (TGL Japan):
Hanabusa Bldg. 2nd Floor
5-2-3 Soto Kanda, Chiyoda-ku Tokyo 101-0021
Tel: 03-3834-5491
Fax: 03-3834-5492
TGL Nagoya Laboratory 3-2-9 Sakae, Naka-ku
Nagoya, Japan
Tel: 052- 264-3027 Fax: 052-264-3028
TGL Osaka Laboratory
2-11-13 Minami Senba, Chuo-ku
Osaka, Japan
Tel: 06- 241-1585 Fax: 06-542-0081
Tokyo Gem Laboratory (Thailand) Co., Ltd.
55/11 501 Charoenkrung 42/1, New Road,
Bangkok Thaailand
Tel: 66-2- 2357324
Three separate private corporations operating under the
same name. Kunihiko Jogan, President Tokyo Laboratory
Shoji Yamazaki, President Nagoya Laboratory
Hiroko Niinobe, President Osaka Laboratory
Diamond grading and gem identification.
Special Equipment:
Diamension FTIR
Services Offered:
Diamond grading, and gem identification, seminars for
retailers employee training.
Carat weight, colore, clarity, cut (symmetry and polish),
cut grades (5 grades as defined by AGL rules: Excellent,
Very Good, Good, Fair and Poor).
Educactional Programs:
Certification Programs are not available. Private classes
are held for clients.

Gem Science Laboratory:
Miyachi Main Bldg. 6Floor
4-30-8 Taito Taito-ku
Tokyo Japan
Tel: 03-383-325521
Fax: 03-383-325504
Osaka Branch is scheduled to open on March 1, 1999
Private Corporation Yoshiki Kikuchi, President
Sorting (pre-grading) shooting gem photography, shooting
gem pictures under microscope.
Special Equipment:
Diamension, a special camera for gem photography.
Services Offered:
Issuance of Diamond Grading Report and Gem Identification
Gem Identification Reports come in three diffrent size.
in full identification report: Identification conclusion,
appearance, shapes, weight, size, date of test, refractice
index, optic character, specific gravity, hardness,
magnification, fluorescence, pleochroism, absorption
spectrum, material, remarks and picture of identified stone,
mounted or unmounted.
In medium ID Report: Conclusion, shape, appearance,
weight, size, comments, list of gemstones and picture of
stone(s) identified in mounting.
In pocket-size ID: Size, measurements, identifiction
conlusion, inscription found on mounting, if any enhance-
ment or treatment and pictur of stone(s) identifode in
mounting. Deamond grading reports come in two diferent
size. In full grading report: Shape and cut, measurments,
weight, clarity grade, JJA/AGL verified master stone number,
color grade, Fluorescence cut grade (AGL standard), propo-
rtions (depth percent, table percent,girdle description, culet
description), finish (polish, symmetry), comments, color
grading scale, clarity grading scale, and picture of graded
diamond. In pocket-size report: Carat, color, clarity, cut,
shape, size, fluorescence, proportions (depth percent, table
percent, girdle dscription, culet description), finish (polish
and symmetry) comments and picture of graded diamond.
Educactional Programs:
Certification rograms are not available, but seminars for
retailers are held on request.

Central Gem Laboratory:
Miygi Bldg., 5-15-14 Ueno, Taito-ku
Tokyo 110-0005 Japan
Tel: 03-3836-3219
Fax: 03-3832-6861
Okachimachi Branch: Taiyo Bldg. 2nd Floor
5-15-17 Ueno
Taitoku 110-0005, Japan.
Nagoya Branch: Sakaecho Nishikan Bldg. 5th Floor,
3-22-13 Nishiki,
Nagoya-shi, Aichi 460-003 Japan
Osaka Branch: Idemitsu Nagohori Bld. 4th Floor
3-4-26 Minami Senba, Chuo-ku
Osaka 542-0081 Japan.
Hakata Branch: BS Bldg. 2nd Floor, 3-19-14 Hakata
Ekimae, Hata-ku
Fukuoka 812-0011, Japan
Antwerp Branch: c/o HRD, Hoveniersstraat 22B-2018
Antwerp, Belgium.
Kofu Office: Teleport Bldg. Hara 2nd Floor
2-16-2 Aioi, Kofu,
Yamanashi 400-0858, Japan
Diamond Museum: Jewelers Town Oramu 4th Floor
1-26-2 Higashi Ueno, Taito-ku
Tokyo 110-0005, Japan
Private Corporation Nobuo Horiuchi, President.
Diamond grading and gem identification.
Special Equipment:
EDX (Energy Dispersive X-ray Fluorescence), Laser
Tomography, FT-IR (Fourier Transform Infrared
Spectrophotometer), Ultra Violet Visible Recording
Spectrophotometer, Soft X-ray Radiography
Aparatus, Multi-task Polarizing Microscope,
Colorimeter, Spectrolino, Cape Detector.
Services Offered:
Diamond grading, gem identification, education,
research, publishing.
On Gem identification: Description of cuts, weight,
identification of color stones, description of treaments
and enhancement (according to AGL Association of
Gemological Laboratories) if any Stones are identified
as loose or mounted. In the case of mounted stones,
appearance (in jewelry) is also reported. Apart from
Gem Identification Report, Analysis Report is issued
identifying the origin of stone and existence of
enhancement. On Diamond Grading Report: cut,carat,
color, clarity, cut grade. Grading reports are issued on
loose stones and mounted stones, however mounted,
stones must be pre-sorted by CGL. Treated stones are
not graded according to AGL rules.
Educactional Programs:
CGL DC (Diploma of central Gem Laboratory) is
given to those who complete the CGL course. The
five-month course teaches basic knowledge of gems,
identification of gems, and grading.