Yes sure, here I am telling you the contact details of some good Diploma in Gemology correspondence colleges in India:

Indian Institute Of Gemology
10980, East Park Road, Karol Bagh, New Delhi, Delhi 110005, India ‎
+91 11 2352 0974 ‎

Indian Gemological Institute
F - 32, First Floor, Flatted Factory Complex, Jhandawalan., NH 10, Jhandewalan, New Delhi, Delhi (state) 110055, India ‎
+91 11 2777 9732 ‎

Gemmological Institute Of India
187/189, 29, Gurukul Chs, Mumbadevi Road, Kalbadevi, Mumbai - 400002, India ‎
+91 22 2342 0039 ‎

Gem & Jewellery Export Promotion Council, The
No. 391/ A, 5th Floor, Diomand Plaza, Dr. D B Marg, Mumbai, Maharashtra, India ‎