What dictates an emerald’s price is mainly the 4Cs of color, clarity, cut, and carat weight in that order. However, there are other factors that heavily impact price too like treatments, international customs, number and arrangements of inclusions, and more.
The 4Cs of value are pretty obvious, since these are entirely dependent on how the cut emerald looks. There is no concrete evaluation before this, because the skill of the gem cutter is what determines the quality of the faceted rough.
The cutter’s skills also determine the amount of carat weight retained from the rough crystals they cut, and how much they can make from their trade overall. A bad cutter can produce low-quality gems from high-quality crystals, wasting precious material.
Ideally Colored and Clear Emerald
E1237 | medium | play
Emerald ID: E1237 – Weight: 2.12 – Origin: Zambia – Price: $10,091.20
If the quality is low enough however, larger gems can be less expensive than smaller ones. For example, emerald E914 to the right is much larger than E1237 above, yet it is less than half the price due to its dark inclusions showing against the bright, green color. Despite the size, it is much lower quality overall.
E914 | medium | play
Emerald ID: E914 – Weight: 3.26 Carats – Origin: Ethiopia – Price: $4,824.80
Emeralds cannot take many treatments due to their inclusions. They also cannot be heated since that makes them lose their color. The main treatments used on them are oil and resin filling for the fractures. This makes them less visible and improves the emerald clarity overall. Oil is usually preferred over resin because the resin cannot be removed cleanly, though there are some places that claim they can with their specialty resin.
The few emeralds that are untreated and have relatively few inclusions are made incredibly expensive due to the rarity.
Part of the cost is driven by transportation of these items. Emeralds mainly come from Columbia in South America and Zambia in Africa, which means they are overseas imports. Sometimes there are trade bans on certain items due to political problems, which makes the price on goods bought and sold before the bans skyrocket.