6810.11.00.10 - Containing by weight more than 70 percent magnesia, expressed as MgO, with carbon content ranging from trace amounts to less than 30 percent, and chemically bonded by resin or pitch

This HTS classification, 6810.11.00.10, specifically covers building blocks and bricks that are primarily composed of magnesia (more than 70% by weight, expressed as MgO). A key characteristic of these articles is their carbon content, which must range from trace amounts up to, but not including, 30%. Furthermore, these magnesia-based building materials are chemically bonded, meaning they utilize resin or pitch as the binding agent, distinguishing them from those bound by cement or other materials.

At this level of detail, this category is distinguished from its sibling, 6810.11.00.70, which is designated for "Other" building blocks and bricks within the broader category of tiles, flagstones, bricks, and similar articles. The "Other" category would encompass magnesia-based building blocks and bricks that do not meet the specific chemical composition or bonding requirements outlined in 6810.11.00.10.

As this is a leaf node within the HTS, there are no further subcategories to introduce. The classification is defined by the precise material composition (high magnesia content), carbon percentage range, and the specific binding agents (resin or pitch). Therefore, accurate classification relies on verifying these technical specifications of the imported or exported goods.