Nether Quartz is awesome, I feel that there could be more uses for it though. I feel that it's rarity is like Iron Ores it should have more uses!
First my suggestion to make glass breakable when a few projectiles hit it, and glass panes breakable with a single projectile. Plexiglass much more resistant than regular glass. Many people in the world today are beginning to replace glass windows with plexiglass.
Minecraft has magic and brewing, so arguably, Minecraft isn't set in the stone age. While you may argue that it's useless. Concrete is the basis of building today, (once dry) they can withstand floods, high winds, immaculate weight, even defend from high speed projectiles. They used them in World War II to defend from explosions! So save your buildings from creepers!
I figured you can combine clay with quartz to get 4 Cement dust, wet the cement ceperately with bottles of water and place it all together to get the the Cement block. eventually the cement will harden and it will become concrete. (I'd love for someone to create a mod for this.)
If you stand on the cement it should act like quick sand and also slow you down.
All I have for now... Don't be afraid to post any of your ideas.
The Meaning of Life, the Universe, and Everything.
Plexiglass wouldn't fit in Minecraft, so how about making it some transparent strong material? Something like... Quartz Glass? I don't know. The concrete suggestion is good, but individual bottles being used to make cement wouldn't work. How about putting them in a bucket of water to create a bucket of wet cement? You can put it on the ground and it'll flow as slowly as lava.
Dude... they've released one snapshot with nether quartz, you can't really say "there could be more uses for it" when it has just been implemented like 2 days ago Anyway, maybe in the future they could make some kind of new light fixture with it that acts like a torch but looks more aesthetically pleasing, Im not quite sure about the plexiglass or concrete, because what purpose would that serve? We already have glass panes and stone. Quartz is only used for modern things nowadays Back in the day it was probably used for jewelry, I dunno, Im not sure what they could possibly use it for, because it is a difficult thing to find uses for
All in all this post, whilst obviously detailed, is a bit like asking Lapis to be turned into Rocket fuel. It makes no sense and is useless and doesn't fit into the game. This is what quartz looks like IRL by the way:
1. "Plexiglass" is in quotes, like how plexi glass is more resistant to damage, it will take longer to destroy.
2. We have brewing so i just said it was like magic.
3. I was more or less stating what it's real world use is.
4. Obsidian for defence is stupid, it's not looks, but its the overall availability, finding 3 diamonds and also spending over 3 minutes mining enough to be able a 2 x 2 house inside is inconvenient.
5. Quartz is used in cement to make it stronger, as a mineral it also helps with water resistance. I also figured because adding it in game as a resistant and asethically pleasing block it needs a buff, Nether Quartz works rather well as a balance.
No support. concrete would be useless. since there is no floods or winds in minecraft. Also. Magic and brewing was a huge belief back in stone age (AD 500ish). In fact, if the chinese didn't beleive in those 2 things. we would not have fireworks and gun-powder related items. Plexi-glass would be useless plainly. It would make it extremely OP because Skeletons don't see through glass. so they wouldn't shoot at the glass. and you only said it could be destroyed by "High speed projectiles".