Low hydrogen content

• Long hydrocarbons chains have all their bonds to the sides passivated by hydrogen. They have a huge surface to volume ratio.
• Crystolecules have a hydrogen free lattice inside. They have a small surface to volume ratio.

Gemstone metamaterial technology is a hydrogen saving (and aldo quite dry operating) technology.
If some intelligent aliens somewhere out there (not saying there are) would use such a technology, than
looking for water and hydrogen to detect them would likely be looking the wrong way.

Raw materials / resource molecules

• Acetylene has low hydrogen content H:C = 1:1
• Methane has high hydrogen content H:C = 4:1
• Long hydrocharbon chains have medium hydrogen content H:C = 2:1

Colonization of the solar system

Outer solar system:
The huge amount of volatile elements in there (especially water with lots of hydrogen) is not very useful as building material.
Sidenote: Nitrogen ice like e.g. on pluto also has limited use on its own.

Inner solar system:
The scarcity of hydrogen at some placed (Moon, Venus, Mercury) may nbe not too big of a problem. Also gemstone metamaterials can emulate soft materials from materials only made from nonvolatile elements. Excluding all the hydrocarbon polymers we know from earth.