Sintered corundum with a micro crystalline structure, consisting of aluminium oxide (CAS|RN|1344-28-1), magnesium aluminate (CAS|RN|12068-51-8) and the rare earth aluminates of yttrium, lanthanum, and neodymium, with a content by weight (calculated as oxides) of: -|92|% or more, but less than 98,5|% of aluminium oxide, -|2|% (± 1,5|%) of magnesium oxide, -|1|% (± 0,6|%) of yttrium oxide, and -|either 3|% (± 2,2|%) of lanthanum oxide or -|2|% (± 1,2|%) of lanthanum oxide and neodymium oxide, with less than 50|% of the total weight having a particle size of more than 10|mm

Sintered corundum with a micro crystalline structure, consisting of aluminium oxide (CAS RN 1344-28-1) and magnesium aluminate (CAS RN 12068-51-8), with a content by weight (calculated as oxides) of: -92 % or more, but not more than 94 % of aluminium oxide, and -8 % (± 1 %) of magnesium oxide

Sintered Sol-Gel corundum or pre-sintered Sol-Gel with a microcrystalline structure, consisting of aluminium oxide, with a composition by weight (as oxides) of at least 92% but less than 98.5% aluminium oxide

Fused alumina with a titanium dioxide content of 1% by weight or more, where both of the following apply: (i) between 5% and 35% of the product by weight is below the lowest grain size limit set out in the specification for the product and; (ii) between 1% and 10% of the product by weight is above the upper grain size limit set out in the specification for the product