Elk or Deer horn is more soft and porous, colour from creamy-yellowish-browny-white to almost white, also it's more accesible and renewable material - obtained by gathering naturally felt animal horns. Skulls on photo from 1st message are from Elk horn. In second message (OgNasty) it's Deer horn.
Mammoth tusk is ANTIQUE! Obtained by
mining in Siberia, Alaska - with extreme conditions.
It's age from 10,000 to 40,000 years. It is precious bone material (like Elephant Tusk, or Ivory - but it's prohibited worldwide).
http://storage9.static.itmages.ru/i/14/1113/h_1415911454_7300544_c83c518751.jpgColour can vary from almost white-beige to creamy-brown, greenish-blue, almost black, and it has unique reticulated structure.
For example, this made from mammoth (photo on my phone, so quality is not the best) :
https://s-media-cache-ak0.pinimg.com/564x/19/c0/30/19c0305c920e6cf11a41c9c48082f487.jpgSo, Mammoth is noble and precious material that obtained by a narrow margin and is non-renewable. Just like Bitcoin
When all mammoth tusk digged out, it's price will rise up as hell.
I will add one example of desk-composition mammoth mosaic skull today, it shows all the difference..
Also mammoth is more heavy and warm..
It like compare Bog Oak and Pine Tree materials
P.S. If you want just a keychain - pick horn. If you want to collect a really cool stuff that will have cost increasment with time -
https://s-media-cache-ak0.pinimg.com/236x/51/8a/bd/518abd7d15613155013fe769eb01d2b3.jpg pick mammoth.
