Eight months into the war in Ukraine, and eight rounds of frantic negotiations later, Europe’s sanctions against Russia run hundreds of pages long and have in many places cut to the bone.

Since February, the European Union has named 1,236 people and 155 companies for sanctions, freezing their assets and blocking their access to the bloc. It has banned the trade of products in nearly 1,000 categories and hundreds of subcategories. It has put in place a near-total embargo on Russian oil. About one-third of the bloc’s exports to Russia by value and two-thirds of imports have been banned.

But even now some goods and sectors remain conspicuously exempted. A look at just a few items reveals the intense back-room bargaining and arm-twisting by some nations and by private industry to protect sectors they deem too valuable to give up — as well as the compromises the European Union has made to maintain consensus.

The Belgians have shielded trade in Russian diamonds. The Greeks ship Russian oil unimpeded. France and several other nations still import Russian uranium for nuclear power generation.

The net impact of these exemptions on the effectiveness of Europe’s penalties against Russia is hard to assess, but politically, they have allowed the 27 members of the bloc to pull together an otherwise vast sanctions regime with exceptional speed and unanimity.

“Ultimately, this is the price of unanimity to hold together this coalition, and in the grander scheme of things the sanctions are really working,” said Jacob Kirkegaard, a senior fellow in the Brussels office of the research group the German Marshall Fund, citing Russia’s diminished access to military technology as evidence.

“We would love to have everything included, diamonds and every other special interest hit, but I am of the opinion that, if sparing them is what it takes to keep everyone together, so be it,” he added.

The Ukrainian government has criticized some of the exemptions, with President Volodymyr Zelensky chiding European nations for continuing to permit business with Russia, saying they are skirting sacrifices

“There are people for whom the diamonds sold in Antwerp are more important than the battle we are waging. Peace is worth much more than diamonds,” Mr. Zelensky said to the Belgian Parliament during an address by video link in late March.

The continued success of Belgium and the broad diamond sector in keeping the Russian diamond trade flowing exemplifies the sacred cows some E.U. nations refuse to sacrifice, even as their peers accept pain to punish the Kremlin.

Exports of rough diamonds are very lucrative for Russia, and they flow to the Belgian port of Antwerp, a historically important diamond hub.

The trade, worth 1.8 billion euros a year — about $1.75 billion — has been shielded in consecutive rounds of the bloc’s sanctions, despite being raised as a possible target soon after the Russian invasion of Ukraine in late February.

The Belgian government has said that it has never asked the European Commission, the E.U. executive body that drafts the measures, to remove diamonds from any sanctions list and that if diamonds were added, it would go along.