A Black powder type comet using 40-60 mesh titanium.
20-40 mesh "sponge" Titanium in a small Fountain
20-50 mesh "sponge" Titanium powder
Titanium can be added to the burst of small shells to give a neat effect.
Description: Metallic titanium is used in pyrotechnics to produce bright white sparks of a superior quality. The particle size and shape of the titanium will affect the colour and duration of the sparks, with smaller mesh producing smaller and shorter-lasting sparks. The effect of a titanium-fountain is superior to all effects that can be obtained with aluminium or magnalium for that purpose.
Hazards: While it will not react with any pyrotechnic chemicals, Titanium can spark if hit with other metals (especially steel) or against itself. Black powder like compositions containing titanium, such as often used in fountains, are notably more sensitive than mixtures without titanium.
Sources: Titanium powder is commonly sold by dedicated pyrotechnic suppliers, and some metal suppliers. Titanium shavings and curls are sometimes available from places where titanium metal is worked. These are often contaminated with oil which can be removed by washings with white gas or acetone. Titanium curls can be heated in an oven to make them more brittle, which facilitates crushing them into a powder. Ball milling of titanium to very fine powders can be made pyrophoric and due to the hardness of the material it is likely to cause excessive damage to the Barrel and Media.
http://en.wikipedia.org/wiki/Titanium | Wikipedia's page on Titanium