F. Diamonds

1. General topics

Niessing primarily works with diamonds in the brilliant cut. The brilliant cut means 56 facets and one table. This cut lends a diamond its fascinating sparkle.

Most diamonds used by Niessing in wedding rings or jewelry rings are intentionally sized conservatively. Up to 0.25 ct. Tension rings and other solitary rings can also hold larger stones up to 10 ct.

Niessing has its own diamond laboratory. Every new diamond is examined here carefully by experts before use. Our stones are purchased at diamond exchanges or from renowned diamond dealers.

2. The 4 Cs

Diamond is the hardest material that exists. And it is also one of the most fascinating. Its name says it all: invulnerable (Greek: adamas). As a symbol for purity and courage, it has been treasured as a precious stone above all others for centuries. Diamonds are rated by cut, color, clarity and carat (the 4 Cs).

Cut. Niessing prefers the brilliant cut: a circular face, 32 facets and one table in the top part, 24 facets in the bottom part. A perfectly shaped precious stone that shines in all the colors of the rainbow thanks to the cut and the extremely high optical refraction. The cut quality is ranked as very good, good, medium and poor.

Color. White or colorless diamonds are very rare. Diamond experts differentiate between exceptional white/River (D, E), rare white/Top Wesselton (F, G), white/Wesselton (H), slightly tinted white/Top Crystal (I), tinted white/Crystal (J), faint yellow/Top Cape (K), yellowish/Cape (L) and yellow/Yellow (Y) (color designations according to GIA). In addition to the yellow series, there is also a brown series that appears in sherry colors. Naturally colored red, green and blue diamonds are extremely rare.

Clarity. Diamonds are natural products and often exhibit mineral inclusions, cracks and growth imperfections. Internally flawless (IF) diamonds exhibit no inclusions under 10 times magnification. Very very small inclusion (VVS) means an inclusion that is difficult to identify with magnification. Very small Inclusion (VS) means identifiable with magnification. Small inclusion (SI) means easy to identify with magnification. P1-P3 (first to third piqué) means identifiable with the naked eye.

Carat. The weight. One carat (ct) corresponds to 0.2 grams. The term originates from the original unit of weight: the seed of the carob tree (Greek: to keraiton). The weight of very small diamonds is also specified by points: 1 point = 0.01 ct.

3. The Kimberley process

Niessing works exclusively with diamonds that are certified according to the "Kimberley process". The Kimberley process is a worldwide system for certifying raw diamonds that verifies the legal origins of the stones.

Niessing works with this guarantee system for producers and dealers. If a diamond has been legally imported, it can be traded, cut, polished and integrated into jewelry. Multiple companies can be involved in this process. Every time a diamond passes from one hand to another, it must be accompanied by a guarantee noted on the invoice that proves the stone did not originate from a conflict region. Manufacturers and dealers are obligated to verify this system of guarantees and to archive the data for five years as part of their annual inspections.


4. Diamond certificates

Diamond certificates contain all the important features of a diamond and help to determine its value. In Europe, the quality standards for certification of diamonds are issued by the CIBJO (Confédération International de la Bijouterie, Joaillerie, Orfèvrerie des Diamantes, Perles et Pierres).

Niessing recommends certificates from all laboratories recognized by the CIBJO and from the following laboratories:
- DDI (Deutsches Diamant Institut, Pforzheim; German CIBJO laboratory) www.isu.de/dseiten/ddi.html
- DPL (Diamant Prüf-Labor, Idar-Oberstein, Germany) www.diamant-prueflabor.de
- HRD Hoge Raad voor Diamant (Antwerp) www.hrd.be
- GIA (Gemological Institute of America, USA) www.gia.org
- AGS (American Gem Society, USA) www.ags.org 


5. Delivery of diamonds for tension rings

You have a diamond of your own that you would like worked into a tension ring? We would be happy to set your stone with a weight starting at 0.25 ct. You can state during the order process whether you would like to use your own stone. Requirement: The diamond must meet at least the quality "si1" required by Niessing or better. Only then will it withstand the pressure of the ring over time. Please have the diamond inspected by an expert according to CIBJO criteria (see "4. Diamond certificates“) and send us the stone insured and with customs paid to our address:

Gebr. Niessing GmbH & Co.
Attn. Ms Anita Niestegge
Butenwall 117
D-48691 Vreden
Germany
ph +49 (25 64) 300-0
service@niessing.com

If you live in America, you can send the stone to our workshop in Los Angeles:

Niessing Los Angeles
Attn. Mrs. Martina Nowak
Brentwood Gardens 11677 San Vicente Blvd. # 101
Los Angeles, CA 90049
USA
ph +1 (310) 820 80 97
losangeles@niessing.com

In this case, the base ring will first be manufactured in the desired size in Germany and then sent to our workshop in Los Angeles. There your diamond will be set into the ring groove by our goldsmith.