Our Diamond & Gemstone Grading Criteria

Grading Options Available

Guthrie’s are able to source a wide range of diamond grades for you, to request a ring using a different grade diamond than specified below simply leave us an enquiry here and we will talk you through your options.

If you are wanting to buy this online that isn’t a problem, we are able to take online payments, credit card over the phone or a bank transfer.

Diamond Grades

Large Diamond Grades Quoted

All Diamonds over 25pts are priced on the following criteria unless otherwise stated. Clarity: SI2, Colour G, Cut: Triple Excellent for Round Brilliants, A minimum of VG for fancy shapes.


All Emerald Cut, Asscher Cut & Princess Cut Diamonds are priced at VS2. All of Guthrie’s Diamonds are Eye Clean.

Small Diamond Grades Quoted

All diamonds below 25pts are based on grades DEF, SI+, various grading options available upon request.

Gemstone Grades

Precious Gemstones

Sapphires are priced upon ceylonese Sapphire’s, Emeralds are quoted on origin unkownn, and rubies are quoted on burmese. These prices are based on a medium to vivid colour. All of Guthrie’s gemstones come free from a reasonable amount of inclusions.

Semi Precious Gemstones

As everyone of these gemstones is unique, we will make contact with you to either view, or send photo’s of your chosen gemstone.


All of Guthrie’s Diamonds come certified by the GIA or the Gemological Institute of America. GIA are the benchmark in diamond grading and have the strictest standards, so you know you are getting value for money.

You can read more about GiA by clicking the link here.

Ethical Sourcing

We have very strict standards in ethical sourcing of all of our diamonds and gemstones. Guthrie’s have gone to great lengths to ensure no one is harmed in the making of jewellery.

We only use trustworthy suppliers, who can guarantee us the material they are supplying checks out 100% of which have been vigorously checked and tested by us.