diff --git a/GUI/Model/Sample/ItemWithMaterial.cpp b/GUI/Model/Sample/ItemWithMaterial.cpp
index 946ffeaaf5cecc7c734922f4835b084f97584a4f..18737504502a8596db7b726bcd079e2816dc74c9 100644
--- a/GUI/Model/Sample/ItemWithMaterial.cpp
+++ b/GUI/Model/Sample/ItemWithMaterial.cpp
@@ -29,7 +29,6 @@ const QString MaterialId("MaterialId");
 ItemWithMaterial::ItemWithMaterial(const MaterialsSet* materialModel)
     : m_materials(materialModel)
 {
-    ASSERT(m_materials);
 }
 
 void ItemWithMaterial::setMaterial(const MaterialItem* materialItem)
diff --git a/GUI/Model/Sample/MesocrystalItem.cpp b/GUI/Model/Sample/MesocrystalItem.cpp
index 6d830f45eec74a00889b8e1e9256bcc9b2cf753e..8769ea3d12db891135191945c68abaaa2ab92fb8 100644
--- a/GUI/Model/Sample/MesocrystalItem.cpp
+++ b/GUI/Model/Sample/MesocrystalItem.cpp
@@ -47,9 +47,8 @@ const QString position_tooltip = "Relative position of the mesocrystal's referen
 
 } // namespace
 
-MesocrystalItem::MesocrystalItem(const MaterialsSet* materials)
+MesocrystalItem::MesocrystalItem(const MaterialsSet*)
     : ItemWithParticles(abundance_tooltip, position_tooltip)
-    , m_materials(materials)
 {
     m_vectorA.init("First lattice vector (nm)", "Coordinates of the first lattice vector",
                    "vectorA");
@@ -59,7 +58,7 @@ MesocrystalItem::MesocrystalItem(const MaterialsSet* materials)
                    "vectorC");
 
     m_outer_shape.initWithArgs("Outer Shape", "", FormfactorsCatalog::Type::Box);
-    m_basis_particle.initWithArgs("Basis", "", ParticlesCatalog::Type::Particle, materials);
+    m_basis_particle.initWithArgs("Basis", "", ParticlesCatalog::Type::Particle, nullptr);
 }
 
 void MesocrystalItem::writeTo(QXmlStreamWriter* w) const
@@ -92,7 +91,8 @@ void MesocrystalItem::readFrom(QXmlStreamReader* r)
         else if (tag == Tag::OuterShape)
             XML::readTaggedElement(r, tag, m_outer_shape);
         else if (tag == Tag::BasisParticle) {
-            m_basis_particle.readFrom(r, m_materials);
+            MaterialsSet* dummy = nullptr;
+            m_basis_particle.readFrom(r, dummy); // TODO rm dummy arg
             XML::gotoEndElementOfTag(r, tag);
         } else if (tag == Tag::ExpandMesocrystalGroupbox)
             expandMesocrystal = XML::readTaggedBool(r, tag);
diff --git a/GUI/Model/Sample/MesocrystalItem.h b/GUI/Model/Sample/MesocrystalItem.h
index 0c0d81c5845d5ac6ec787d6bfdd54b495d4e360b..434ba543cfa5b369834afa0e748bfc88ec309ca3 100644
--- a/GUI/Model/Sample/MesocrystalItem.h
+++ b/GUI/Model/Sample/MesocrystalItem.h
@@ -72,7 +72,6 @@ private:
     VectorProperty m_vectorC;
     PolyItem<FormfactorsCatalog> m_outer_shape;
     PolyItem<ParticlesCatalog> m_basis_particle;
-    const MaterialsSet* m_materials;
 };
 
 template <typename T> T* MesocrystalItem::setOuterShapeType()