Lithium quartz
If you want to use these in the mini crystal layout suggested, place the lithium quartz over your Ajna (third eye). The lithium in lithium quartz is what gives them the pink/red/brown tinge. Lithium is one of the ingredients used in modern antidepressant medications. This crystal is great for stress reduction, depression and especially anxiety. If you only have this crystal out of the 3 listed in this post you can alternatively place it on your heart chakra or higher heart/thymus gland - here the energy will eventually move up top your third eye anyway.
Aquamarine
Aquamarine has a beautiful refreshing but deep energy. A water element stone that helps wash away and soothe stress and anxiety. Aquamarine is also an amazing stone to help you reduce and manage grief; it helps you to release anger, and instills courage, making it easier if you are transitioning through change. It is perfect for this use even if the cause of the issue is a deep rooted one of the past, rather than something that is happening now. Aquamarine also helps you to speak your truth in difficult situations, whether that is inner conversations with yourself or expressing yourself to others. If you are following the suggested mini layout place aquamarine over your throat chakra.
Mangano Calcite
Mangano Calcite is a premier stone in reducing anxiety. It’s message and medicine is one of support, compassion and forgiveness for yourself and others. Even though its vibration is gentle it is a powerful crystal with its soothing effects often felt in minutes by many. Mangano calcite ranges from pink to very light pink/white, sometimes with faint banding or swirly patterns on large or raw pieces, some smaller tumbled pieces appear just one colour all over. Once again if you are following the mini layout suggestion place this crystal in the center of your chest - heart chakra area or the higher heart/thymus gland. If you have all 3 of these suggested crystals feel free to play around with positioning of these crystals.
If you are worried about becoming ‘ungrounded’ whilst trying this mini layout, you can always place a grounding stone on your root chakra, at your feet or beneath your feet - if you're laying down, for your earth star chakra, or simply hold some in your hands.
Some suggested grounding crystals; Hematite, Black Tourmaline, Flint, & Black Obsidian.