The coasters shown here depict Oxygen and Silicon, which combine to make Silica, one of the main ingredients in glass. So, for me, these would be perfect. Why not make a present personalised for your special someone? Some suggestions below...
For coffee lovers - Caffeine! (Chemical formula C8H10N4O2, so you could buy a set of four with Carbon, Hydrogen, Nitrogen and Oxygen)
For any borderline alcoholics you know - Ethanol! (Chemical formula C2H6O, so a set of three with Carbon, Hydrogen and Oxygen)
For the traditional romantic - The precious metals set! Why not buy a gold (Au), Platinum (Pt) or Silver (Ag)?
Personalised for career or studies - I have had someone purchase tin (Sn) for their friend who did a PHD on tin, and a purchase of a set of lead (Pb) coasters for a plumber friend!
Personalised for names - How about Silicopn (Si) for your good pal Simon?
Personalsied for your favourite TV show or song - Anyone for some Bromine (Br) and Barium (Ba)? Or how about Titanium (Ti) for your favourite song?
The possibilities are endless, and awesome, and isn't chemistry just kind of neat??
For some more inspiration, why not have a look at the old peridoc table... http://en.wikipedia.org/wiki/File:Periodic_table.svg
I have printed these coasters in Neo Lavender glass, merely because I like the colour, it has nothing to do with the colour categories on the periodic table. Your coasters will be made to order on any colour glass.
Also available, The element of SURPRISE!! https://www.etsy.com/listing/117161805/the-element-of-surprise-coaster-made-to