Is Crystal Mines II: Buried Treasure on Steam?

No. Crystal Mines II: Buried Treasure is not distributed on Steam, so there is no Steam Charts or SteamDB player count for it. Its live popularity is tracked here via Twitch viewership instead.

What platforms is Crystal Mines II: Buried Treasure on?

Crystal Mines II: Buried Treasure is available on Atari Lynx.

When did Crystal Mines II: Buried Treasure release?

Crystal Mines II: Buried Treasure was first released on December 31, 2003.

Crystal Mines II: Buried Treasure

Dec 31, 2003PuzzleAtari Lynx

Crystal Mines II: Buried Treasure — frequently asked questions

Is Crystal Mines II: Buried Treasure on Steam?: No. Crystal Mines II: Buried Treasure is not distributed on Steam, so there is no Steam Charts or SteamDB player count for it. Its live popularity is tracked here via Twitch viewership instead.
What platforms is Crystal Mines II: Buried Treasure on?: Crystal Mines II: Buried Treasure is available on Atari Lynx.
When did Crystal Mines II: Buried Treasure release?: Crystal Mines II: Buried Treasure was first released on December 31, 2003.

About Crystal Mines II: Buried Treasure

In 2000, Songbird Productions produced a sequel, Crystal Mines II: Buried Treasure on CD-ROM for Microsoft Windows. This CD-ROM required the original game and a Lynx to PC serial cable to run, allowing the editing and creation of all new levels. This was followed in 2003 by a cartridge release of Crystal Mines II: Buried Treasure with the original 181 levels and 125 new levels.

Summary via IGDB.

Crystal Mines II: Buried Treasure on Wikipedia

Crystal Mines II is a puzzle video game designed and programmed by Ken Beckett for Color Dreams. It was licensed to Atari Corporation for the Lynx handheld system. The game is a sequel to Crystal Mines for the Nintendo Entertainment System. Both releases are similar to Boulder Dash, a genre which has since become known as "rocks and diamonds" games.

Source: Wikipedia (text under CC BY-SA 4.0).