In permineralization (fossil preservation, altered remains), is there a good substitute for silica (quartz)?
Yes. At normal air pressure sand will melt at 573 degrees centigrade. If you can control its cooling rate you can grow crystals. If you let it cool too fast it will form amorphous (no specific crystal shape) glass, also called obsidian. (And often sold as Apache tears, small polished tear drops of silica). The trick is to control the cooling and it is a very difficult trick to do at home. But it is done industrially all the time and in large scale, both small and large crystals. It is not true that it takes high temperature and pressure (there is quartz in a different crystal class that does form at high temperature and pressure, called beta quartz but once the temperature and pressure come off it changes its crystallization and becomes common low temperature (alpha) quartz. IN fact nearly microscopic animals called diatoms form quatrz constantly at sea water temperatures. THe process is not well understood yet.
sand is already quarts its just small. but if the large crystal is what ur looking for then you would have to super heated it then submitted it to ridicules amounts of pressure then it would be a quartz crystal.
I dont think that the quartz itself would be the problem, but like Elliot said, the jagged edges could injure the betta. A good test for bettas is rubbing the object against some pantyhose and if it snags on the pantyhose at all, you know that it can do the same to the betta's fins.
