There are two ways to submit an item for testing to GCS

1.On-site testing

You are welcome to visit our premises at 30 New Bond Street, W1S 2RN.If you have not used our services before, you must not visit without a confirmed appointment. To book your visit, please complete the New Client Registration Form and submit it via email to contact@gcslab.co.uk in advance. For booking inquiries or further details, you can also call us directly on +44 (0)207 491 4777.

2. By shipping

Before shipping the item(s) please fill in and sign the Submission Form, include it in your parcel and send us an email.

A parcel received without a signed submission form will not be processed.

You can ship your item(s) to us using the courrier of your choice.
If you are in the UK, we recommend using the Royal Mail Service (Tracked, Next Day Delivery).
If you are outside the UK, please use the courrier of your choice.

You will have to organise your pick-up and collection; and send us the relevant documents to place on the parcel for the return.
If unsure, don’t hesitate to contact us on +44 (0)207 491 4777 or by email contact@gcslab.co.uk

All items submitted to GCS will be subject to the Terms and conditions.

Download New Client Registration Form
Download Submission Form

3. Important Guidelines for Submitting Gemstones

• Before submitting items to our laboratory, please review our standard testing requirements:
• Polished & Faceted Stones Only: We do not accept rough gem materials. All gemstones must be fully polished or faceted prior to submission, with a minimum size of 0.25 ct per individual stone.
  Turnaround Times: Testing is a detailed diagnostic process and does not happen on the spot or on the same day. We strictly do not offer a same-day testing service. Our standard turnaround time is on average 10 to 15 working days.