Exhibition Review: Green Diamonds: Natural Radiance

Loose and mounted green diamonds.
Figure 1. Loose and mounted stones are part of the Natural History Museum of Los Angeles’s Natural Radiance green diamond exhibition. Left: A 4.17 ct Fancy Vivid yellowish green unmounted diamond. Centre: A 1.53 ct Fancy Intense green diamond ring set in platinum. Right: An unmounted 1.92 ct Fancy Vivid green yellow diamond. Photos © Optimum Diamonds.
Green is among the rarest colours found in natural diamond; this hue is caused by gamma radiation while the stones are still deep within the earth. Since there are comparatively few of these specimens available, it is remarkable to find an entire exhibition dedicated to them. Green Diamonds: Natural Radiance, at the Natural History Museum of Los Angeles (NHMLA), showcases eight displays of more than 60 loose and mounted diamonds in various shades of green (figure 1). The exhibition was curated in partnership with New York–based Optimum Diamonds, which specialises in rare and exotic natural-colour diamonds. The stones on display were collected over the course of 20 years as part of Optimum’s Gamma Green collection.

Unmounted green diamonds in different hues.
Figure 2. Unmounted green diamonds on display include a 0.47 ct Fancy Deep bluish green (left), a 0.58 ct Fancy Vivid green (centre), and a 1.92 ct Fancy Intense yellow green. Photos © Optimum Diamonds.
The exhibition itself is in a private room in the back of the museum’s esteemed Gem and Mineral Vault. While other gem materials are displayed in the room, the green diamonds rightfully take centre stage. More than 30 loose faceted stones are on display, in hues ranging from greenish blue to green-yellow (figure 2), a valid representation given how rarely these colours are found in natural diamond. One display was set aside for chameleon diamonds, which change from their natural greenish yellow colour to brown or orange when exposed to heat or light. Of particular interest among these rarest of gemstones was a 3.08 ct Fancy Dark grey greenish yellow chameleon diamond (figure 3).

Two chameleon diamonds.
Figure 3. These two pear-shaped stones, a 3.08 ct Fancy Dark grey greenish yellow on the left and a 2.15 ct Fancy Deep brownish green yellow on the right, were included in the chameleon diamond display. Photos © Optimum Diamonds.
Green diamonds mounted in jewellery.
Figure 4. Left: The Wild Orchid ring incorporates two green diamonds (weighing 0.86 and 0.76 ct) in a titanium setting. Right: The Caribbean earrings, inspired by the tropical locale, each have at their centre a Fancy Vivid blue-green diamond weighing more than 4 ct. Photos © Optimum Diamonds.
The jewellery pieces chosen to showcase these diamonds—mostly rings—are nothing less than exquisite. While some, like the Wild Orchid ring and the Caribbean earrings (figure 4) use stones of multiple colours, shapes and sizes to achieve a striking effect, many others use simple, classic-cut colourless stones as accents, allowing the green diamond to be the true centrepiece. Figure 5 shows two such examples: a 2.01 ct Fancy Vivid green-yellow square cut surrounded by a square border of colourless stones, and 4.94 ct Fancy Deep yellowish green oval in a timeless, elegant setting. The Nautilus ring and matching earrings merge these concepts, with a free-form design that features a Fancy Vivid blue-green stone at its centre, to great effect (figure 6).

Green diamonds in rings.
Figure 5. Many of the jewellery pieces in the exhibition, such as the rings shown here, allow the green diamond to occupy centre stage with designs that are simple yet elegant. Left: The colour of the 2.01 ct Fancy Vivid green-yellow diamond is emphasised by the surrounding square border of colourless stones. Right: In this timeless ring, colourless diamonds frame the 4.94 ct Fancy Deep yellowish green centre stone. Photos © Optimum Diamonds.
Nautilus ring and earrings
Figure 6. The Nautilus ring and earrings, set in white gold, each have a Fancy Vivid green-blue diamond at their centre. The diamond in the ring weighs 1.55 ct; the diamonds in the earrings are 1.04 ct and 1.20 ct. Photos © Optimum Diamonds.
The displays provide details about the general nature of diamonds and the causes of their colour, along with each specimen’s carat weight. The museum notes briefly that radiation was identified as the source of the green colour in 1904, when “an unnamed scientist” (Sir William Crookes) buried white diamonds in radioactive salts; there are also brief explanations of diamond geology and the nature of chameleon diamonds. It was a pleasant surprise to find this information available in both English and Spanish. However, it would have been nice to have more information on the formation and radiation of these rare stones, perhaps in the form of wall signage. The room is also rather darkly panelled and dimly lit; a brighter environment might have shown these stones to their best advantage. And while there are only a few well-known green diamonds, some basic information to educate the visitor on famous gemstones such as the Dresden Green, the Ocean Dream and the Aurora Green would have been a welcome addition.

Green Diamonds: Natural Radiance adds a bit of panache to an already delightful trip to NHMLA. The exhibition is a must for any diamond aficionado with an eye for colour. 
Green Diamonds: Natural Radiance is on view at the Natural History Museum of Los Angeles until 1 April 2018. Admission is $15 for adults; $12 for seniors 62 and over, students with school IDs and young people ages 13–17; and $7 for children ages 3–12. Los Angeles County residents receive free museum admission Monday–Friday from 3.00 to 5.00 pm. The museum is open from 9.30 to 5.00 pm seven days a week; it is closed on New Year’s Day, the Fourth of July, Thanksgiving and Christmas Day.

Jennifer-Lynn Archuleta is the editor of Gems & Gemology.