Rutile, Granular

Same mineral, different grain size. Powdered rutile blends into the glaze and gives the flowing, streaky "rutile" look. Granular rutile is coarse, so each grain leaves a small dark speck or burst of color.

Stir granular rutile into the wet glaze after you sieve it, starting at 0.5 to 1% (half a gram to 1 gram for every 100 grams of dry glaze). If you sieve after adding it, the sieve catches the grains. For a speckled clay, mix a small amount into the dry clay ingredients before adding water.

The grains may have been caught in the sieve, there may not have been enough rutile, or an opaque glaze may have covered them. In very runny glazes, the grains can melt into streaks instead of specks. Add it after sieving, try a little more, and test on a tile.

Glaze and clay recipes go by weight, not by volume, and they don't count water. Each ingredient is a share of the dry total. 2% means 2 grams for every 100 grams of dry ingredients. For a 500-gram batch, that's 10 grams. Colors and opacifiers are often listed as extras on top of a recipe that adds up to 100, written like "+2" or "add 2%." Weigh those the same way: 2 grams for every 100 grams of the base recipe. A digital scale that reads to 0.1 gram makes small amounts easy.

A test tile is a small piece of the clay you use, glazed and fired just like your real work. Raw materials vary from bag to bag, and results also change with your clay, how thick you apply the glaze and how your kiln fires. A test tile is the only way to know what you'll get before you glaze a whole batch of pots. Write what's on each tile on the back (an underglaze pencil works), and keep notes so you can repeat what works.

Yes, whenever you handle the dry powder. Fine dust is the main hazard with most raw materials, and some can harm your lungs over time. Wear a NIOSH-approved respirator (N95 or better) while you weigh and mix. A basic dust mask that isn't N95-rated won't protect you. Once a material is mixed with water, dust is much less of a problem, but wipe up spills with a wet sponge before they dry, and mop instead of sweeping. Don't eat or drink while you work, and wash your hands afterward. Check each product's Safety section for anything extra that material needs.