Glass is made of melted Silicon Dioxide, or sand

Yes, that brittle irritating stuff that gets in everything makes glass

Sale 1

http://www.tf2outpost.com/trade/27097320 Sold for DBD Trilby + 2.6 keys of sweets

Trilby had no trade, presuming offered

X = 26*0.9 + 2.6*0.9

X = 26

Trilby http://backpack.tf/item/3321234847

Front http://backpack.tf/item/2193226593

Trade http://backpack.tf/profiles/76561198175249965?time=1444287600&compare=1444374000

Mini for Trilby

http://backpack.tf/vote/id/5679d45ddea9e978487f7654 26 keys, using 26

Sale 2

http://www.tf2outpost.com/trade/27296669 Sold for Duped GE Beret

X = 26

Beret http://backpack.tf/item/1756639571

Runner http://backpack.tf/item/2207094539

Trade http://backpack.tf/profiles/76561198049267666?time=1445670000&compare=1445756400

Mini for Beret

http://www.tf2outpost.com/trade/27322249 Sold for Steaming Coldsnap + 3 keys

B/O for Coldsnap was 25

Beret had no trade, presuming offered

X = 25*0.9 + 3

X = 26

Coldsnap http://backpack.tf/item/3350497995

Beret http://backpack.tf/item/1756639571

Trade http://backpack.tf/profiles/76561198131077446?time=1446537600&compare=1446624000

Seller

http://www.tf2outpost.com/trade/27274434 30 keys, unsold for 2m